Roger Federer is winning again.

The top-ranked Swiss won the Estoril Open and his first title of the season when second-seeded Nikolay Davydenko retired with a left leg injury while trailing 7-6 (5), 1-2 yesterday.

Nikolai Davydenko, from Russia, left, has a laugh with Roger Federer, from Switzerland, while holding the trophies after the final match of the Estoril Tennis Open, in Oeiras, outside Lisbon, yesterday. Federer won 7-6, 1-2, after Davydenko retired due to an injury.

Federer even managed to add another personal first with his 54th career title.

"I think it's the first time in my life I play a final and someone gave up," Federer said. "I guess if you put yourself in the position so many times it's going to happen eventually, but you don't hope for it."

Federer managed to get an awkward season back on track in windy conditions on his hardest surface.

"It's great to win a title again and to straightaway win my first clay court tournament of the season gives me great confidence going into Monte Carlo," the 26-year-old Swiss said. "I guess now, if you get better conditions, (I'll) play so much better."

Federer returned to his winning ways in his fifth tournament played this season. It had been eight years since Federer had needed so many events to reach a final.

"Two months ago when I didn't have enough matches and because of my sickness everything looked a little more up in the air," said Federer, who had been diagnosed with mononucleosis.

Davydenko, who fell to 0-12 against Federer, didn't notice much difference in his opponent.

"He had good control, he kept the same (play) as before," the Russian said. "I don't see anything different between (the) last matches and now."

Federer added Estoril to his schedule in a bid to boost his chances of winning the French Open. The 12-time Grand Slam winner also recruited clay court specialist Jose Higueras to help win the only major championship missing from his collection.

Federer leveled his record in clay court finals to 7-7 on a day where the cold conditions brought on by intermittent rain left both players reacting rather than dictating the play.

"Today was just the toughest conditions. You can't chase the line any more at all, you just try to keep the ball in play," Federer said. "It's just not easy to play aggressive tennis, it's more of a waiting game."

Davydenko had broken Federer to start the second set before pulling out of the match.