Novak Djokovic, who will lead Serbia in its Davis Cup semifinal against Canada in Belgrade this weekend, admits that he is tired after his loss to Rafael Nadal in the U.S. Open final on Monday night. Djokovic took an overnight flight to Belgrade after hosting his foundation’s charity gala in New York City.

The world No. 1 will face Canada’s Vasek Pospisil in Friday's opening singles match.

“It’s not the first time I’ve had just two days to get ready for the Davis Cup after long-haul flights,” Djokovic told reporters in Belgrade. “The 2011 experience was not a great one when I faced [Juan Martin] del Potro in the semifinal against Argentina because I was injured, apart from being exhausted, and we lost the tie. I am tired and jet-lagged as I couldn’t get here before Wednesday, but I am fit now and we haven’t played at home in the Davis Cup for two years. Hence I am as motivated and inspired as ever to play for my country in this team event.”