Novak Djokovic beat Rafael Nadal 6-1, 7-5 on Saturday to reach the final of the Cincinnati Masters and bring the Spaniard's 32-match unbeaten streak to a halt.
Serb Djokovic will meet Andy Murray in the final after the 21-year-old Briton overcame giant Croatian Ivo Karlovic in the day's other semi-final.
Nadal, who is set to replace Roger Federer as world number one, was a shadow of the player who romped to the Wimbledon and French Open titles this year. He conceded before the match that he was struggling.
"No one is unbeatable but the way he was playing we all thought he's not going to lose any time soon," said Djokovic.
"I tried not to think of his winning streak and what his new ranking spot will be. I tried just to focus on my game.
"It was my intention to have a fast start and to step in and go for it. And in the second set I just tried to stay with him."
Australian Open champion Djokovic got off to a roaring start and broke Nadal's opening two serves to go 5-0 up before taking the first set in less than half an hour.
Nadal made a fight of it in the second, carving out a break point at 3-2, but Djokovic saved it with a fierce forehand.
Five games later Djokovic made the crucial break after a series of brilliant baseline rallies before closing out the match.
Briton Murray reached his first Masters Series final when he beat Karlovic 6-4, 6-4 and the semi-final victory guarantees his rise from world number nine to six, his highest ranking.
It also increased the chances of achieving his goal of a top-eight seeding at the US Open in three weeks' time.
Maintaining the momentum that carried him to the quarter-finals of Wimbledon for the first time last month and the semi-finals of the Masters Series in Toronto last week, Murray won well against a uniquely difficult opponent.
The 2.08-metre Karlovic leads the tour for the second successive year for the number of aces and the number of service games won.
Briefly it seemed that Karlovic might build on his career-best success after earlier knocking out Federer when he broke the Murray serve to go 2-0 up. But the canny Scot found a way to return the tour's best serve.
Murray frequently stood more than two metres behind the baseline to receive, but often leaped forward to take the delivery earlier than expected. His ability to anticipate the location of Karlovic's serves improved as the game went on.
Murray broke back right away and again to go 4-3 ahead before sealing the first set.
Karlovic managed to get some good ground strokes going in the second set and the match was balanced at 4-4, but Murray eventually broke the serve-volleyer down to reach the final.