( CNN ) -- Argentina 's Juan Martin del Potro became the second player in the world 's top 10 to withdraw from the French Open when a viral infection ruled him out of Sunday 's championships in Paris . The world No . 7 revealed that the virus had affected him when losing to Frenchman Benoit Paire in last week 's Rome Masters . The 24-year-old 's withdrawal follows that of world No . 2 Andy Murray , who pulled out of the year 's second grand slam with a back injury . `` This is a tough blow , because these are the events you dream of winning , '' said del Potro , who won the U.S. Open in 2009 , on the ATP website . `` Now I must get over this disappointment and recover completely in order to prepare at 100 % for the tests to come . '' The virus affecting Del Potro had prompted the tall right-hander to miss recent tournaments in Portugal and Madrid , and he returned in Italy with the hope of being able to compete at the French Open . Despite his exit in the third round , he will always remember his time in the Italian capital after meeting with the Pope , a fellow Argentine , last week -- an experience del Potro said he would `` never forget '' . Del Potro reached the semifinals of Roland Garros in 2009 and the quarterfinals last year -- only to be beaten by Roger Federer on both occasions . He was joined in withdrawing from next week 's event by former world number seven Mardy Fish , who is now ranked 41st in the world , and fellow American Brian Baker -- whose absences had been expected . Also on Wednesday , Caroline Wozniacki 's terrible 2013 continued when the number one seed was beaten in straight sets by China 's Zheng Jie at the Brussels Open . The former world number one from Denmark is on a terrible recent run of form , having now added a first round exit in Brussels to those suffered in Italy , Spain and Germany in the last month alone . The latest loss was all the more humbling given that Zheng had been on court four hours earlier to see off American qualifier Mallory Burdette in the first round . Wozniacki , who had received a bye into the second round , was beaten by Zheng 's aggressive tactics with the Chinese hitting twice as many winners as the Dane ( 34 to 17 ) . `` She 's a very tough player and fought until the last point , '' Zheng was quoted as saying by the Women 's Tennis Association website . `` I 'm so happy I could win this match . We 've played many times before and she 's always so tough to beat . `` But she 's also a very nice person , ever since she was a junior . I 'm very proud and this gives me a lot of confidence . '' Zheng will play Romina Oprandi of Switzerland in the quarterfinals , while Wozniacki must work out how to rediscover the form that took her to April 's Indian Wells final ahead of Sunday 's French Open .
Virus forces Juan Martin del Potro out of French Open . Argentine ##an illness enforced stops in Portugal and Spain . Former world no . 1 Murray suffers another first round exit .