US' Brian Baker returns the ball to Russia's Nikolay Davydenko, during his semi-final match at the Nice ATP tennis tournament, southern France, Friday, May 25, 2012.

US's Brian Baker returns the ball to Russia's Nikolay Davydenko, during his semi-final match at the Nice ATP tennis tournament, southern France, Friday, May 25, 2012.

US's Brian Baker reacts during his semi-final match against Russia's Nikolay Davydenko, during the Nice ATP tennis tournament, southern France, Friday, May 25, 2012.

Sweden's Sofia Arvidson returns the ball during the semi finals of the Brussels open against Roumania's Simona Halep, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Radek Stepanek of Czech Republic returns the ball to his opponent Leonardo Mayer of Argentina during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Sweden's Sofia Arvidson returns the ball during the semi finals of the Brussels open against Roumania's Simona Halep, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Sweden's Sofia Arvidson returns the ball during the semi finals of the Brussels open against Roumania's Simona Halep, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Leonardo Mayer of Argentina returns the ball to his opponent Radek Stepanek of Czech Republic during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Romanian Simona Halep returns the ball during her semi-final game against Sweden's Sofia Arvidsson, at the WTA Brussels Open, on May 25, 2012. The second edition of the WTA Brussels Open tennis tournement is taking place from May 19 to 26, 2012. Halep won in two sets, 6-4 and 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR ***Belgium Out***VIRGINIE LEFOUR/AFP/GettyImages

Romanian Simona Halep returns the ball during her semi-final game against Sweden's Sofia Arvidsson, at the WTA Brussels Open, on May 25, 2012. The second edition of the WTA Brussels Open tennis tournement is taking place from May 19 to 26, 2012. Halep won in two sets, 6-4 and 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR ***Belgium Out***VIRGINIE LEFOUR/AFP/GettyImages

Romanian Simona Halep celebrates after winning her semi-final game against Sweden's Sofia Arvidsson, at the WTA Brussels Open, on May 25, 2012. The second edition of WTA Brussels Open tennis tournement is taking place from May 19 to 26, 2012. Halep won in two sets, 6-4 and 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR ***Belgium Out***VIRGINIE LEFOUR/AFP/GettyImages

Roumania's Simona Halep returns the ball during the semi finals of the Brussels open against Sweden's Sofia Arvidson, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Roumania's Simona Halep returns the ball during the semi finals of the Brussels open against Sweden's Sofia Arvidson, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Roumania's Simona Halep returns the ball during the semi finals of the Brussels open against Sweden's Sofia Arvidson, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

A picture taken on May 25, 2012 shows the official poster of French Open tennis tournament in Paris. The Paris' Grand Slam tournament takes place at the Roland Garros stadium from May 22 to June 10, 2012. AFP PHOTO JACQUES DEMARTHONJACQUES DEMARTHON/AFP/GettyImages

Spain's Nicolas Almagro reacts between two sets of his semi-final match against France's Gilles Simon, at the Nice ATP tennis tournament, Friday May 25, 2012, southern France.

Spain's Nicolas Almagro backhands the ball to France's Gilles Simon during their semi-final match at the Nice ATP tennis tournament, Friday May 25, 2012, southern France.

France's Gilles Simon reacts during his semi-final match against Spain's Nicolas Almagro at the Nice ATP tennis tournament, Friday May 25, 2012, southern France.

France's Gilles Simon reacts during his semi-final match against Spain's Nicolas Almagro at the Nice ATP tennis tournament, Friday May 25, 2012, southern France.

Spain's Nicolas Almagro backhands the ball to France's Gilles Simon during their semi-final match at the Nice ATP tennis tournament, Friday May 25, 2012, southern France.

France's Gilles Simon reacts during his semi-final match against Spain's Nicolas Almagro at the Nice ATP tennis tournament, Friday May 25, 2012, southern France.

Spanish player Rafael Nadal reacts as he takes part in the draw of the Tennis Women's Single of the Roland-Garros tennis tournament on May 25, 2012 at the Roland-Garros stadium in Paris. AFP PHOTO/JACQUES DEMARTHONJACQUES DEMARTHON/AFP/GettyImages

Spanish player Rafael Nadal takes part in the draw of the Tennis Women's Single of the Roland-Garros tennis tournament on May 25, 2012 at the Roland-Garros stadium in Paris. AFP PHOTO/JACQUES DEMARTHON JACQUES DEMARTHON/AFP/GettyImages

Spanish player Rafael Nadal takes part in the draw of the Tennis Women's Single of the Roland-Garros tennis tournament on May 25, 2012 at the Roland-Garros stadium in Paris. AFP PHOTO/JACQUES DEMARTHONJACQUES DEMARTHON/AFP/GettyImages

Radek Stepanek of Czech Republic returns the ball to his opponent Leonardo Mayer of Argentina during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Radek Stepanek of Czech Republic returns the ball to his opponent Leonardo Mayer of Argentina during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Leonardo Mayer of Argentina returns the ball to his opponent Radek Stepanek of Czech Republic during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Radek Stepanek of Czech Republic casts a shadow as he serves to his opponent Leonardo Mayer of Argentina during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Radek Stepanek of Czech Republic returns the ball to his opponent Leonardo Mayer of Argentina during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Radek Stepanek of Czech Republic returns the ball to his opponent Leonardo Mayer of Argentina during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Leonardo Mayer of Argentina returns the ball to his opponent Radek Stepanek of Czech Republic during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Leonardo Mayer of Argentina returns the ball to his opponent Radek Stepanek of Czech Republic during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Leonardo Mayer of Argentina returns the ball to his opponent Radek Stepanek of Czech Republic during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Estonia's Kaia Kanepi returns the ball during the semifinal match of the Brussels open against Poland's Agnieszka Radwanska, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Estonia's Kaia Kanepi returns the ball during the semifinal match of the Brussels open against Poland's Agnieszka Radwanska, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Poland's Agnieszka Radwanska returns the ball during the semifinal match of the Brussels open against Estonia's Kaia Kanepi, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Poland's Agnieszka Radwanska returns the ball during the semifinal match of the Brussels open against Estonia's Kaia Kanepi, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Poland's Agnieszka Radwanska returns the ball during the semifinal match of the Brussels open against Estonia's Kaia Kanepi, at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Poland's Agnieszka Radwanska returns the ball to Estonia's Kaia Kanepi during the semifinal match of the Brussels Open at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Poland's Agnieszka Radwanska returns the ball to Estonia's Kaia Kanepi during the semifinal match of the Brussels Open at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Estonia's Kaia Kanepi returns the ball to Poland's Agnieszka Radwanska during their semifinal match of the Brussels Open at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Estonia's Kaia Kanepi returns the ball to Poland's Agnieszka Radwanska during their semifinal match of the Brussels Open at Royal Primerose Tennis Club in Brussels, Friday May 25, 2012.

Agnieszka Radwanska from Poland returns the ball to Varvara Lepchenko from U.S. during the Madrid Open tennis tournament, in Madrid, Friday, May 11, 2012.

Estonia's Kaia Kanepi returns a shot to Polish Agnieszka Radwanska during their WTA Brussels Open semi-final tennis match, on May 25, 2012. Radwanska won 7-6 / 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR Belgium OutVIRGINIE LEFOUR/AFP/GettyImages

Polish Agnieszka Radwanska returns a shot to Estonia's Kaia Kanepi during their WTA Brussels Open semi-final tennis match, on May 25, 2012. Radwanska won 7-6 / 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR Belgium OutVIRGINIE LEFOUR/AFP/GettyImages

Polish Agnieszka Radwanska returns a shot to Estonia's Kaia Kanepi during their WTA Brussels Open semi-final tennis match, on May 25, 2012. Radwanska won 7-6 / 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR Belgium OutVIRGINIE LEFOUR/AFP/GettyImages

Estonia's Kaia Kanepi returns a shot to Polish Agnieszka Radwanska during their WTA Brussels Open semi-final tennis match, on May 25, 2012. Radwanska won 7-6 / 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR Belgium OutVIRGINIE LEFOUR/AFP/GettyImages

Polish Agnieszka Radwanska waves as she celebrates winning her WTA Brussels Open semi-final tennis match against Estonia's Kaia Kanepi, on May 25, 2012. Radwanska won 7-6 / 6-3. AFP PHOTO / BELGA / VIRGINIE LEFOUR Belgium OutVIRGINIE LEFOUR/AFP/GettyImages

Italy's Andreas Seppi, left, and Flavio Cipolla talk during a joint training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Italy's Andreas Seppi volleys the ball during a training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Italy's Flavio Cipolla returns the ball during training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

PARIS, FRANCE - MAY 25: Li Na of China smiles as she speaks to members of the media during a press conference ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Li Na of China looks on during a press conference ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Rafael Nadal of Spain hits a forehand during a practice session ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

Germany's Philipp Kohlschreiber reacts after losing against Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber reacts after losing against Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia reacts after winning against Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia reacts after winning against Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia reacts after winning against Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

PARIS, FRANCE - MAY 25: Serena Williams of USA speaks to members of the media during a press conference ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Serena Williams of USA speaks to members of the media during a press conference ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Novak Djokovic of Serbia stretches to hit a backhand during a practice session ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Rafael Nadal of Spain hits a forehand during a practice session ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Novak Djokovic of Serbia stretches to hit a backhand during a practice session ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Roger Federer of Switzerland serves during a practice session ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

PARIS, FRANCE - MAY 25: Roger Federer of Switzerland serves during a practice session ahead of the French Open at Roland Garros on May 25, 2012 in Paris, France. (Photo by Dan Istitene/Getty Images)

Switzerland's Roger Federer reacts during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer reacts during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Serbia's Novak Djokovic smiles during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer reacts during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer, foreground, returns the ball as he trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Janko Tipsarevic of Serbia returns to Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia returns to Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia returns to Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia returns to Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Janko Tipsarevic of Serbia returns to Germany's Philipp Kohlschreiber during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber returns to his opponent Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber reacts during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber returns to his opponent Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber returns to his opponent Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber returns to his opponent Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Germany's Philipp Kohlschreiber serves to his opponent Janko Tipsarevic of Serbia during the World Team Cup tennis tournament at the Rochusclub in Duesseldorf, Germany, Friday, May 25, 2012.

Switzerland's Roger Federer, second right, steps over the net, during a training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer returns the ball as he trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer reacts during a break as he trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Switzerland's Roger Federer is to slam the ball as he trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Russi'a Maria Sharapova answers reporters during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Russi'a Maria Sharapova answers reporters during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Russi'a Maria Sharapova answers reporters during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Defending Na Li answers reporters during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Defending Na Li answers reporters during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Defending Na Li answers reporters during a press conference for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Serbia's Novak Djokovic react during a training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Serbia's Novak Djokovic drinks during a training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Serbia's Novak Djokovic returns the ball during a training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Defending champion Spain's Rafael Nadal rests during a training session for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Defending champion Spain's Rafael Nadal returns the ball as he trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.

Defending champion Spain's Rafael Nadal returns the ball as he trains for the French Open tennis tournament at the Roland Garros stadium in Paris, Friday, May, 25, 2012.