Nikolay Davydenko ended seven years of pain against Roger Federer on Saturday, finally beating the world number one 6-2, 4-6, 7-5 to reach the final of the ATP World Tour Finals for a second successive year.
The Russian had lost all 12 of his previous clashes with the Swiss magician since they first met in 2002 but produced an inspired performance in front of 17,500 captivated fans inside the O2 Arena to resist a Federer fightback.
He set up a final showdown with 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.
Watched by WBA World heavyweight champion David Haye, Del Potro delivered the knockout punch -- an ace -- to end the see-saw contest after two hours and 11 minutes.
"I'm very happy to make my first final ... one more match before my holiday," an exhausted Del Potro told the crowd.
Federer had been the only player in the current top 10 that Davydenko had failed to beat and the 28-year-old's victory was even more impressive given he was on court late on Friday battling to secure a semi-final place while the world number one had his feet up in the hotel.
It had looked as though all Davydenko's hard labour would count for nothing as Federer produced a shot of outstanding audacity to move within two points of victory in the 10th game of the deciding set, but the Russian held his nerve to advance.
"I just thought: 'OK, if I lose, tomorrow I go home and the next day I go to the Maldives for a holiday,'" Davydenko told reporters after arguably the best victory of his career.
"I had no pressure. I knew I was playing good."
Federer, who can now get back to helping out with his twin daughters and preparing for next season, said he paid the price for a poor start, a feature of his matches here where he lost the first set in all three of his round-robin matches.
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"It's disappointing ... just to lose in the semis," said Federer, a four-times winner of the year-ending tournament.
"Coming so far in a tough group, in a tough tournament, I had hopes to get through to the final and maybe win again. But I missed the start again, and I guess that's what cost me the match at the end.
"He proved it was worth hanging in there. He finally beat me today and I wish him all the best for the final."
Few would have given Davydenko any chance at all, especially as he had managed to win just four of the 32 sets he had contested against 15-times grand slam champion Federer.
One fan in the cavernous, dimly-lit arena held up a banner which read: "I just flew 3,000 miles just 2 C King Rog"
He probably thought he had booked tickets for the wrong event in the first set as Federer was unrecognisable, dropping serve three times in succession to hand Davydenko the opener.
Federer's serve began to click in the second set and he dominated the baseline rallies, although Davydenko was undaunted until a lame forehand when serving at 4-5 gave Federer the chance to level the match.
Things came to the boil at the same stage of the third set with both men playing at the peak of their powers. Federer moved in for the kill, moving 0-30 ahead on the Russian's serve, meeting a Davydenko smash with a leaping, swerving overhead of his own to leave Davydenko shaking his head in disbelief.
However, the Russian responded to reel off the next four points and then found the baseline with one of his pinpoint backhands in the next game to break Federer's serve.
As he served for the match, Davydenko slipped 30-40 behind but he came back with a sizzling forehand winner and claimed victory in one hour 55 minutes when Federer netted a return.
"When he hit that smash I thought he was lucky again, I thought: 'No, not again, 13 times in a row, to lose again,'" said Davydenko.