Federico Delbonis continued his strong recent play, eliminating defending champ Thomaz Bellucci in the first round of the Swiss Open on Tuesday.

Delbonis entered this week's event off a runner-up finish in Hamburg. He stunned Roger Federer in the semifinals last weekend before falling to Fabio Fognini in the championship match.

The 22-year-old Argentine came away with a 7-5, 7-6 (7-2) triumph over Bellucci, who also won this tournament in 2009 in addition to last year's title. The Brazilian was also a first-round loser last week in Hamburg.

Spain's Roberto Bautista Agut was the only seeded player in action Tuesday and posted a 6-2, 6-3 victory over Swiss wild card Henri Laaksonen. The eighth- seeded Bautista Agut will next face Romania's Victor Hanescu, a 7-6 (8-6), 6-2 winner Tuesday against German qualifier Dustin Brown.

Three other Spaniards -- Guillermo Garcia-Lopez, Pablo Andujar and Daniel Gimeno-Traver -- also advanced with wins Tuesday.

Garcia-Lopez topped Romania's Adrian Ungur in three sets and will play fourth- seeded Juan Monaco in the second round, while Andujar dropped just three games in a rout of Romanian qualifier Victor Crivoi. Andujar will face sixth-seeded Mikhail Youzhny in round two.

Gimeno-Traver eased past Frenchman Kenny De Schepper in straight sets to earn a second-round date with second-seeded Swiss favorite Stanislas Wawrinka.

Also, Dutchman Robin Haase toppled Brazilian qualifier Joao Souza and will next play third-seeded Janko Tipsarevic in the second round. Tipsarevic was last year's runner-up to Bellucci.

Germany's Daniel Brands went the distance to knock off Swiss wild card Marco Chiudinelli and will take on an even bigger Swiss name in the second round, as the top-seeded Federer awaits.

Federer is playing this event for the first time since winning the title in 2004.