Geneva, Switzerland (SportsNetwork.com) - U.S. Open champion Marin Cilic was a hard-fought second-round winner Tuesday at the Geneva Open, a final clay- court French Open tune-up.

The second-seeded Croat came from behind to beat Russian wild card Andrey Rublev 4-6, 7-6 (9-7), 6-1 at Geneva Tennis Club. Cilic popped 14 aces in the 1-hour, 41-minute affair.

A mild second-round upset occurred when Colombian Santiago Giraldo doused eighth-seeded Russian veteran Mikhail Youzhny 6-4, 6-4.

The first round concluded with four matches on Day 3, as Czech qualifier Lukas Rosol overcame Taiwan's Yen-Hsun Lu 1-6, 7-6 (7-1), 7-5; Argentine Federico Delbonis handled Russian Teymuraz Gabashvili 6-3, 6-4; French qualifier Adrian Mannarino outlasted Argentine Carlos Berlocq 4-6, 6-1, 6-4; and Uzbekistan's Denis Istomin drilled Serbian wild card Janko Tipsarevic 6-0, 6-2.