( CNN ) -- World number one Novak Djokovic could face Roger Federer in the semifinals of the U.S Open after the pair were grouped in the same side of the draw Thursday . Djokovic , the top seed , has lost only twice in 2011 , and has already clinched the Australian Open and Wimbledon titles this season . He has been drawn to play a qualifier in round one . Switzerland 's Federer , who has clinched glory at Flushing Meadows on five previous occasions , begins his campaign with a clash against Colombian Santiago Giraldo . Defending champion and second seed Rafael Nadal will face Andrey Golubev of Kazakhstan as the Spaniard goes in search of an 11th career major . Is Wozniacki feeling the weight of world number one ? Nadal told the U.S. Open 's official web site : `` I feel great . I am here , and I will try my best . Last year was a really emotional year for me . `` It was the tournament I did n't play my best in the past . Last year , I played one of my best matches in the final . I finally won . '' British number one Andy Murray , defeated by Djokovic in January 's Australian Open final , will come up against Somdev Devvarman of India . The top-ranked American in the draw is Mardy Fish , and the 29-year-old eighth seed will look to eliminate German Tobias Kamke in the opening round . The 2009 U.S. Open winner Juan Martin del Potro will go head-to-head with Italy 's Filippo Volandri . In the women 's draw , first seed Caroline Wozniacki will begin her latest attempt to capture a maiden grand slam crown against Spain 's Nuria Llagostera Vives . Vera Zvonareva , ranked second in the world , has been drawn against a qualifier , while 2006 winner Maria Sharapova has been paired with Britain 's Heather Watson . Li Na , winner of the French Open , will have to get the better of Romania 's Simona Halep , while Wimbledon champion Petra Kvitova is up against another Romanian Alexandra Dulghera . Serena Williams has claimed victory at this event three times during her career , and her latest title tilt will commence against Serb Bojana Jovanovski .
World No.1 Novak Djokovic to begin U.S. Open challenge against a qualifier . Defending champion Rafael Nadal drawn to face Andrey Martin of Russia . Caroline Wozniacki in quest for a grand slam against Nuria Llagostera Vives . Two - time winner Serena Williams to face Serb Bojana Jovanovski .