Nikolay Davydenko in London on Sunday. (Reuters)

London: Nikolay Davydenko won the first big tournament of his career Sunday, running down just about every ball and using a consistent serve to beat US Open champion Juan Martin del Potro 6-3, 6-4 to win the elite ATP World Tour Finals.

Davydenko, who eliminated top-ranked Roger Federer in the semi-finals, dominated his service games against Del Potro, losing only five points on serve in the first set and eight in the second.

Del Potro had three chances to break Davydenko, but the Russian saved them all to complete a sweep of all three of this year’s Grand Slam champions at the season-ending tournament.

“For me it was amazing,” Davydenko said. “Coming here as No. 7 and winning the tournament, it was surprising for myself.”

Davydenko also reached the final of last year’s tournament for the top eight players in the world, but he lost to Novak Djokovic. That tournament was played in Shanghai.

Davydenko finished the match with 25 winners and only 15 unforced errors, while Del Potro had 20 winners and 19 unforced errors. Besides facing each other at the O2 Arena, both players had to contend with a crying baby.

While trailing 4-1 in the first set, Del Potro played one point despite the cries of a baby behind him. He lost that point, bringing the score to 40-15. He then waited to serve to while the baby was carried out of the arena.

In the second set, it was Davydenko’s turn to wait while he was serving to even the score at 3-3. He paused while the baby quieted and then held his serve.

This season, Davydenko struggled early in the year with an injury to his left heel, forcing him to withdraw from the Australian Open. But he returned in April, and later reached the quarter finals at the French Open.

He won his fourth title of the season at the Shanghai Masters — a victory needed to help him qualify for the ATP finals — and stretched his record to 5-0 in championship matches in 2009 by beating Del Potro.

In London, Davydenko lost to Djokovic in his opening Group B match, but then beat Australian Open champion Rafael Nadal and French Open finalist Robin Soderling to advance. In the semi-finals, he finally got the better of Federer, who had beaten Davydenko in each of their previous 12 meetings.

Federer won both the French Open and Wimbledon this year and clinched the year-end No. 1 ranking for the fifth time in his career.

“He beat everybody, so he’s a worthy champion,” Del Potro said.

Earlier, Bob and Mike Bryan won the title to reclaim the year-end No. 1 doubles ranking, beating Max Mirnyi and Andy Ram 7-6 (3), 6-3.

It is the third time the American brothers have won the tournament and the fifth time they will end the year as the top-ranked doubles team.

“It means so much,” Bob Bryan said. “It’s pretty much what we play for now. I mean, that’s the goal. Play well in the slams, but the ultimate goal is to finish No. 1.”

The twins got the only break of the final to go up 5-3 in the second set and Bob Bryan then served out the match at love. He fell to his knees in celebration before getting up to catch his brother as Mike jumped into his arms.

The Bryan brothers lost last year’s final to Daniel Nestor and Nenad Zimonjic, a result that dropped them to No. 2 in the rankings behind the Canadian and Serb. Nestor and Zimonjic entered the ATP finals as No. 1 but were eliminated in the round-robin phase.

“We felt like it was stolen from us last year,” Bob Bryan said. “Now we kind of crept up on those guys and stole it from them this year. We feel like it’s a little bit of a payback.”

Mirnyi and Ram beat the twins in the round-robin phase of the tournament, but couldn’t repeat the feat in the final.

“We like playing against them. We beat them three times this year, once this tournament,” Ram said. “We feel like we have the game, the right game to beat them.”

The Bryan brothers wasted three break points in the first set, taking a 40-0 lead in the seventh game. But Mirnyi and Ram held on and won the next four points — the point after deuce decides the games — to even the score at 4-4.

In the tiebreaker, Mirnyi and Ram took a 5-4 lead with a service winner from the tall Belarusian, but the Americans won the next three points to claim the first set.

“Max returned great, Andy played awesome,” Mike Bryan said. “It made for some great rallies out there. Feel fortunate to come out on top. They’re a great team. It’s a shame they’re splitting up next year. But all credit to them, they had a great year.”