Roger Federer of Switzerland reacts after a matchpoint against Nikolay Davydenko of Russia during their semi final men's singles tennis match at the World Indoor Tournament in Rotterdam, the Netherlands February 18, 2012.[Photo/Agencies]??

ROTTERDAM - Top seed Roger Federer battled past Russian Nikolay Davydenko in an entertaining 4-6 6-3 6-4 triumph on Saturday to reach the World Indoor Tournament final.

The Swiss former world number one now faces third seed Juan Martin Del Potro of Argentina who brushed aside second-seeded Czech Tomas Berdych 6-3 6-1 in Saturday's first semi-final.

Federer, who has admitted struggling with the surface and his rhythm, recovered after losing the first set having been broken in the ninth game and early in the second set.

Davydenko dominated from the baseline using his powerful forehand but dropped his serve in the sixth game of the second with Federer taking four straight games to force a decider.

Davydenko wasted four break points in the third set while Federer, whose serve was never convicning, failed to take six chances before finally breaking to love to settle the match.

"We often played big matches and today again," said Federer. "It is good so see him performing so well again."

Asked about his previous showdowns with Del Potro ahead of Sunday's final, the Swiss added: "He beat me in the 2009 US Open final in a tough five setter, while our last match at the Australian Open was my 1,000th match on the tour."?