World No. 1 Roger Federer was knocked out of the semifinals by Russian Nikolay Davydenko 6-2, 4-6, 7-5 at the ATP World Tour Finals on Saturday.

It is Davydenko's first victory over Federer in their 13 meetings within seven years.

"I thank all my family, everybody who support me, wait for this moment, you know when I can beat Federer, because I beat everyone in top 10 except Federer," said the Russian "Iron Man".

"I was thinking it may be coming in 2010 or 2011. But in 2009, end of the season, it's a good feeling."

Davydenko, 28, finished second to Novak Djokovic of Serbia in last year's ATP Tour Finals. He edged out the defending champion with a better sets record in Group B.

After ending his season with a loss, Federer said, "It's disappointing. But not to lose against him; just to lose the semis. Coming so far in a tough group, in a tough tournament, I had hoped to get through to the final and maybe win again."

But the Swiss superstar believed he had little regrets this year.

"I play at a very high level usually at the end of tournaments. When you go out, if it's five sets or three sets or straight sets, I know I put in the best effort I could. And then you don't walk away too disappointed. I finished No. 1 in the world. So I don't have many regrets," he said.