Geneva, Switzerland (SportsNetwork.com) - Swiss favorite Stan Wawrinka was among Wednesday's second-round winners at the Geneva Open, a final clay- court French Open tune-up.

The top seed held off Czech qualifier Lukas Rosol 6-4, 3-6, 6-3 at Geneva Tennis Club.

Wawrinka's quarterfinal opponent on Thursday will be Argentine Federico Delbonis, who took care of Russian qualifier Andrey Kuznetsov 6-3, 6-4.

In other second-round play featuring seeds, No. 3 Pablo Andujar of Spain overcame French qualifier Adrian Mannarino 3-6, 7-6 (7-2), 6-2, Spaniard Albert Ramos-Vinolas upended No. 4 Benjamin Becker of Germany 7-6 (7-2), 6-2 and No. 6 Joao Sousa of Portugal handled Austrian Jurgen Melzer 6-4, 6-4.

One other result saw Brazilian Thomaz Bellucci top Uzbekistan's Denis Istomin 6-4, 6-4.

The other quarterfinals will pit second-seeded U.S. Open champion Marin Cilic of Croatia against Colombian Santiago Giraldo, Andujar versus Sousa and Bellucci against Ramos-Vinolas.