Top seed Janko Tipsarevic bowed out, while second-seeded German favorite Tommy Haas was among Wednesday's second-round winners at the $530,000 Power Horse Cup, a final French Open tune-up.
The struggling Serbian Tipsarevic gave way to 101st-ranked Argentine qualifier Guido Pella 7-6 (7-1), 6-1 in 89 minutes, while Haas came from behind to beat Croat Ivan Dodig 3-6, 6-4, 7-5 on the red clay at Rochusclub, which used to play host to the ATP World Team tournament. Tipsarevic is now a pedestrian 11-11 this year.
The 35-year-old Haas was tested mightily by the capable Dodig.
"I was close to losing, down 4-5, 15/30 in the third set. Ivan played a terrific match. It was tough conditions, with rain in between. It wasn't the best for my old bones," Haas said.
Another upset came when Dutchman Igor Sijsling overcame fourth-seeded German Philipp Kohlschreiber 3-6, 6-3, 6-4.
In other second-round action involving seeds, No. 3 Argentine Juan Monaco handled Brazilian qualifier Andre Ghem 6-4, 6-4, No. 6 Finn Jarkko Nieminen held off Spaniard Roberto Bautista Agut 6-4, 5-7, 6-3, and No. 7 Serb Viktor Troicki bested Slovenian Grega Zemlja 6-3, 7-6 (7-3).
Other Day-4 results saw German Tobias Kamke dismiss Slovenian lucky loser Aljaz Bedene 6-1, 6-4 and Czech Jan Hajek blitz German Daniel Brands 6-1, 6-0.
Thursday's quarterfinals will pit Haas against Nieminen, Monaco versus Kamke, Troicki against Pella, and Hajek versus Sijsling.
This week's winner will collect $95,000.