Juan Martin Del Potro defeated Philipp Petzschner of Germany 6-3, 6-4 Wednesday to reach his seventh quarterfinal of the season at the Erste Bank Open.
The second-seeded Argentine, who is seeking one of three remaining spots at next month's ATP finals, saved four break points in the opening set but held serve throughout against Petzschner, who won his only tour title here three years ago.
In first-round play, Steve Darcis of Belgium came back from 4-0 down in the deciding set to upset No. 7 Nikolay Davydenko of Russia 3-6, 6-0, 7-6 (2).
Also, Jarkko Nieminen of Finland defeated Robin Haase of the Netherlands 7-6 (3), 6-4 to set up a second-round match against top-seeded Jo-Wilfried Tsonga.