EASTBOURNE, England (AP) -- Top-seeded Agnieszka Radwanska of Poland failed to reach the second round of the Aegon International when she was beaten 6-4, 3-6, 7-6 (4) by Anastasia Pavlyuchenkova of Russia on Monday.
But defending champion Elena Vesnina of Russia held off a strong challenge to beat Shuai Peng of China 6-3, 6-4, and there was another hard-fought victory for 2012 runner-up Angelique Kerber of Germany, who defeated Alison Riske of the United States 7-6 (6), 6-4.
Radwanska won the grass-court tournament in 2008, but she has since fallen in the first round four times and not won a match at Eastbourne since she reached the quarterfinals in 2011.
Despite her early exit, Radwanska was not too concerned about her lack of match preparation for Wimbledon. In 2012 after a first-round defeat she went on to reach the Wimbledon final, and last year after an opening-round loss she reached the semifinals there.
''The first match (on grass) is always tricky,'' she said. ''Well, it was a great match before Wimbledon to get used to it ... I just hope I can do the same good results (at Wimbledon) this year.''
Wozniacki had to recover a break of serve at the beginning of each set to defeat Stosur but felt comfortable to be back on a surface which netted her the 2009 title at Eastbourne as well as the junior trophy at Wimbledon.
Following her first round defeat at Roland Garros, Wozniacki enjoyed a break in Miami with family and friends, including Serena Williams.
''That was a lot of fun,'' Wozniacki said. ''Serena and I had a good time with some of our other friends ... I came back home and I worked hard every day four, five hours a day. My game is in good shape.''
Eastbourne also features No. 8 Victoria Azarenka of Belarus. A former No. 1, a left foot injury restricted her to just one match since she surrendered her Australian Open title in the quarterfinals in January.
Drawn to face Italian Camila Giorgi in her opening match on Tuesday, Azarenka said, ''It's not important for me who's going to be on the other side. I just want to see what I can do, and just see how to raise my level from there.''
Everyone's mind inevitably is on Wimbledon, which begins next week, but second-seeded Petra Kvitova, who reached the Eastbourne final in 2011 before going on to claim the Wimbledon title, is determined to keep her focus on this week.
''Of course, I want to play the best that I can to get used to the grass and everything before Wimbledon, but I'm taking this tournament as a very big one,'' Kvitova said. ''It's a very tough draw. Everybody wants to be successful here.''
In the men's event, Frenchman Jeremy Chardy beat former two-time champion Ivo Karlovic of Croatia 6-4, 6-4, sixth-seeded Gilles Simon of France defeated Australian qualifier Chris Guccione 7-6 (2), 6-4 and American Sam Querrey beat Britain's Kyle Edmund 7-6 (5), 6-3.