Roger Federer ended his 2008 title drought at the Estoril Open on Sunday after Nikolay Davydenko retired in the second set of their final with a leg injury.

Federer won the first set 7-6 (7/5) after saving two set points, but Russian Davydenko was battling back in the second, claiming an early break before being forced to retire when leading 2-1.

The victory marks a perfect start to Federer's association with claycourt coach Jose Higueras, and his 54th ATP crown will have the 26-year-old in bullish mood ahead of next week's Monte Carlo Masters.

Federer admitted he was unhappy with the circumstances that brought about his first title of the season.

"It feels great to win a title again and the circumstances were unfortunate," he said. "It would have been nice for Nikolay to finish.

"I think it's the first time in my life that someone has retired against me - in 70-80 finals. But it is a great start to the claycourt season to win a title."

Davydenko's misfortune ends a run of 11 consecutive wins on the ATP Tour, which included victories against Andy Roddick and Rafael Nadal en route to the title in Miami last month.

However, he played down fears that his injury could rule him out of the Monte Carlo event.

"When I ran to the left, I felt pain," he said. "I felt the muscles in my left leg stretch at the end of the first set.

"I went to speak to the physio at the end of the tie-break and received a quick massage, but I quickly knew I could not continue.

"I'm playing on Wednesday in Monaco, and I've been told by the physio that he expects me to be okay by then."