Novak Djokovic has had a fine season, and he is now guaranteed to finish the season as world number one. The Paris Masters is a tournament near the end of the season, and it's one that the Serbian player would have been hoping to win.
Therefore, a three-set defeat to American Sam Querry in the second round of the competition would have been hard to take. I think we understand that American tennis is not in the best of places at the moment, and Querry is not even their best player; that accolade belongs to John Isner, who is ranked number 10 in the world.
In contrast, Querry is ranked at number 23 in the world. So, this was the sort of defeat that some may consider to be embarrassing to Djokovic. However, it has been suggested that the Serb has been dealing with issues away from tennis recently.
Nevertheless, the soon to be number one player will want to put a marker down to prove he is fully deserving of that place. To be honest, it's hard to say which male tennis player is most deserving of the spot on top of the rankings.
Obviously, it's a matter of choosing between the top four players because they are the only ones to have won Grand Slam events this season. Djokovic started off the season superbly by winning the 2012 Australian Open. But then Rafael Nadal came in with his now customary win at Roland Garros.
At that point, you could be forgiven for thinking they were the two players to watch. But Nadal's second round defeat at Wimbledon 2012 put him into a psychological and injury nightmare that has meant he hasn't played since. This amount of time out of the game meant he was never a true contender for the number one spot.
Roger Federer won Wimbledon, and Andy Murray picked up the 2012 U.S. Open title. Murray also managed to pick up a gold medal at the London 2012 Olympics. So, many people think that, perhaps, the season should belong to him.
However, the lack of ranking points available for the Olympics and a lack of general consistency have put him out of contention. This year, in terms of ranking, may belong to Novak Djokovic, but he must know that he faces a real challenge to stay on top.
This latest defeat for the Serb, just shows that he is as vulnerable as any other top player is. It will be interesting to see how the World Tour Finals goes and how that will impact the 2013 tennis season.