Basel: Novak Djokovic fell to a shock defeat in the Swiss Indoors semifinals on Saturday, as Kei Nishikori of Japan beat the top-ranked Serb 2-6, 7-6 (4), 6-0.

Nishikori was overmatched in the first set but turned the match around by winning a thrilling rally when Djokovic was just two points from victory at 5-4 in the second.

The 32nd-ranked Nishikori, a wild card entry here, won the second-set tiebreaker then raced away with the final set for a career-best victory. He was already assured of his highest ever ranking when the new ATP list is published on Monday.

"It's unbelievable," said the 21-year-old Japanese. "In the second set I started playing well and getting a rhythm."

Djokovic was twice treated for pain in his right shoulder after having his service broken, but praised Nishikori as a deserved winner.

"He was getting impossible balls back and really making me play every shot," said Djokovic, who was coming off a six-week break to treat a back injury.

Djokovic dropped to 68-4 this year, with two of his losses the result of injury retirements.

Nishikori joins Roger Federer, in the French Open semifinals, as the only players to beat Djokovic over the full distance in 2011.

Defending champion Federer was playing in the other semifinal against his Beijing Olympics gold medal-winning doubles partner Stanislas Wawrinka.

Nishikori was initially outclassed as Djokovic raced to a 5-1 lead, moving his opponent around the court with powerful ground strokes.

Djokovic then lost his serve and called for a medical timeout to treat his right shoulder. Pains in the same shoulder had prompted his retirement in the Cincinnati Masters final in August against Andy Murray.

However, Nishikori then found more service trouble _ managing just a 24 percent first-serve rate in the opening set - and Djokovic took advantage.

Nishikori improved in the second set, and a break to lead 3-2 prompted Djokovic to again call for the trainer.

Djokovic was two points from victory when Nishikori showed tenacity to win a thrilling point that brought both men to the net.

In the tiebreaker, Nishikori profited from Djokovic's wayward double-handed backhands. Nishikori dominated the decider and clinched a famous victory when Djokovic sent another backhand long.