Gstaad, Switzerland (Sports Network) - Third-seeded Swiss favorite Stan Wawrinka and fourth-seeded Russian Mikhail Youzhny were a pair of second-round upset victims Wednesday at the $435,000 Swiss Open Gstaad.

Oft-injured Frenchman Paul-Henri Mathieu upended the 2005 Gstaad runner-up Wawrinka, who fired 10 aces in a losing effort, 7-6 (7-3), 7-6 (10-8) in just over two hours, while Brazil's Thomaz Bellucci came from behind to dismiss Youzhny 4-6, 6-2, 6-4 on the clay courts at Credit Agricole Swiss Arena. Mathieu titled here in 2007, while Bellucci captured this event in 2009.

Meanwhile, fifth-seeded Spaniard Feliciano Lopez avoided an upset by overcoming Czech Jan Hajek 6-7 (3-7), 6-1, 6-4 on Day 3. Lopez, who was a finalist here in 2006, will encounter Bellucci in an all-lefthanded quarterfinal on Friday.

One other second-round result saw Latvian Ernests Gulbis outlast Frenchman Benoit Paire 5-7, 7-6 (7-3), 6-4. Gulbis will take on Mathieu in the quarters.

The first round concluded when seventh-seeded Colombian Santiago Giraldo drilled Swiss wild card Henri Laaksonen 6-2, 6-2.

In some more second-round action on Thursday, top-seeded Serb Janko Tipsarevic will battle Austrian Martin Fischer and second-seeded and defending Gstaad champion Marcel Granollers will face Poland's Lukasz Kubot.

Tipsarevic is fresh off his clay-court title in Stuttgart, while Granollers was a runner-up in Umag last week.

Granollers beat Fernando Verdasco in an all-Spanish Gstaad finale last year.

This week's champion will collect $79,000.

The Sports Network