Roger Federer cruised into the quarter-finals of the Estoril Open with a 6-3, 6-2 win over Romania's Victor Hanescu in a match played in the rain on Thursday.
Despite the conditions, the one-hour match was not halted at any stage by the umpire.
The 26-year-old Swiss was on top form with impressive play from the baseline and a series of backhand winners that eluded his 68th ranked opponent.
"Victor had a really hard time penetrating the ball, he struggled to hit winners and I didn't make too many mistakes," said Federer, adding that he hadn't played under such heavy rain in the last couple of years.
"I played offensive and knew what to do. It was a good match. I'm very happy."
The 12-time Grand Slam winner showed his class by wrapping up the match with an ace on his fourth match point.
Federer, who recently employed clay court expert Jose Higueras to help him recover from a sluggish start to the 2008 season, will next meet the winner of a match between unseeded Portuguese players Joao Sousa and Frederico Gil.
He hasn't won a tournament this season after battling with a stomach virus and mononucleosis.
World number four Nikolay Davydenko of Russia, Estoril title winner in 2003, had already reached the last eight of the clay court tournament with a 2-6, 6-2, 6-4 win over Czech Ivo Minar late on Wednesday.