|Thirteenth time lucky for Russia's Nikolay Davydenko [GALLO/GETTY]
A powerful performance by Russian Nikolay Davydenko knocked the Swiss champion Roger Federer out of the World Tour Finals at a packed O2 Arena in London.
In a masterful display of tennis from both players, Davydenko overpowered the world number one 6-2, 4-6, 7-5 in the semi-final to book a finals berth on Sunday against US Open champion Juan Martin del Potro after the Argentine survived a tight tussle to squeeze past Swede Robin Soderling 6-7 6-3 7-6.
The crowd favourite Federer, who was broken three straight times in the first set, came within two points of winning while leading 5-4 in the third set.
But Davydenko held on to then break Federer to take a 6-5 lead before serving out the win.
It was the Russian's first win over the top-ranked Federer in 13 matches.
Federer again struggled with his serve and his shot-making for much of the match, but he looked in blistering form while serving throughout the third set and held easily through 5-4.
With Davydenko serving to stay in the match, Federer took a 30-0 lead when he returned an overhead smash from Davydenko by running across the court and jumping high to get his racket on the ball.
Davydenko was stunned by the acrobatic return, but he still won the next four points to hold serve.
"I think I have waited a long time to beat once Federer," Davydenko told Sky Sports.
"After 12 times of losing and now here in London winning my first time against him it's amazing for me."
"I knew Federer would try and come back and he tried to win at 5-4 on my serve but he didn't and I came back.
"When he hit that smash I thought he was lucky again, I thought: 'No, not again, 13 times in a row, to lose again'."
Federer, who clinched the year-end No1 ranking after winning his second group match at the season-ending tournament, despite glimpses of brilliance, again did not look like himself at the south east London venue, often misplacing his usual dominating forehand and struggling to hold serve against a player he had never before lost to.
Federer lost the first set in each of his three Group A matches, but managed to beat Fernando Verdasco and Andy Murray before losing to Del Potro - the same man who beat Federer in the US Open final.
|Heartbreak for the crowd favourite [GALLO/GETTY]
Federer was stellar in the opening two games, first holding at love with a pair of aces and then earning a pair of break points in the second game.
But Davydenko saved them both, and he then went on his streak of breaking Federer three straight times. The 15-time Grand Slam champion broke back once.
To start the second set, Federer slowed down his powerful serve, thereby raising his first-serve percentage, and held easily throughout.
However, he still showed his frustration early in the set. After sending a backhand return into the base of the net, the ball came bouncing back toward him and he kicked it over to the other side of the court. That, too, went wide.
But leading 5-4 in that second set, he managed to break Davydenko for the second time when the Russian sent a forehand wide on Federer's second break point.
"I was a couple of points away, but just couldn't get it done,'' said Federer, a four-time champion at the season-ending event.
"He did well. I thought he played strong throughout, even though I don't think it was our best match we ever played against each other.''
"I picked sometimes wrong choice of shots, right from the start,'' Federer said.
"After that, I didn't serve very well in the first set at all.''
"Sure, it's disappointing. But not to lose against him, just to lose the semis,'' Federer said.
"He finally beat me today. I wish him all the best for the final.''