World number one Roger Federer completed the exodus of the top three seeds from the Rome Masters on Wednesday, when he lost 3-6, 6-3, 6-2 to Spain's Albert Costa in the second round.

Federer, who last year finished runner-up in the Italian capital to Costa's compatriot Felix Mantilla, followed in the wake of U.S. Open champion Andy Roddick, the number two seed, and German third seed Rainer Schuettler.

Roddick and Schuettler both suffered opening-round defeats.

Federer, playing his first claycourt tournament of the season, started flawlessly, dragging the 2002 French Open champion around the court with a combination of raking groundstrokes and delicately-angled volleys to cruise through the opening set.

Having failed to convert three break points at the beginning of the second, however, the Swiss allowed his concentration to waver and mistakes crept into his game.

A careless backhand and a wild smash over the baseline gave Costa the break he needed to force the match into a deciding set.

Having exchanged early breaks, four consecutive unforced errors by Federer in the fifth game gifted a vital break to Costa, who then broke again in the seventh to seal Federer's third defeat of the year.