Djokovic reaches Sony final; Nishikori withdraws

KEY BISCAYNE, Fla. — Novak Djokovic advanced to the Sony Open final when Kei Nishikori withdrew less than two hours before Friday's semifinal because of a groin injury.

Nishikori won a grueling three-set match against Roger Federer on Wednesday night and also won a three-setter against David Ferrer in the fourth round, when he saved four match points.

Nishikori tweeted the news after he tried to practice before the match.

"Very disappointed and I am obviously very sorry for any fans," he said.

The No. 2-ranked Djokovic will bid for his fourth Key Biscayne title Sunday against the winner of Friday night's match between No. 1 Rafael Nadal and No. 7 Tomas Berdych.

Djokovic also received a walkover in the third round and has played only six sets in the tournament. He won the Indian Wells title two weeks ago, when he beat Federer in the final.

Regardless of results the rest of the week, Nadal will remain No. 1 and Djokovic No. 2 next week.

Former No. 1 Martina Hingis and Sabine Lisicki advanced to the final in women's doubles by beating Cara Black and Sania Mirza 6-3, 6-4.