Jared Donaldson books Stan Wawrinka clash at Geneva Open

American Jared Donaldson saw off the challenge of Denis Istomin in Geneva to set up a clash against Stan Wawrinka.

The 21-year-old, who lost his five previous matches, came from a set down to beat the Uzbek 5-7, 6-4, 6-0 in one hour, 48 minutes.

Next up for Donaldson is an encounter against third seed and two-time defending champion Wawrinka, who had a bye in the opening round.

Frances Tiafoe also advanced as he came out on top in the all-American match against Ryan Harrison, winning 3-6, 7-6 (7-5), 6-4. He will face either fifth seed Albert Ramos-Vinolas or Hungarian Marton Fucsovics.

Two more Americans advanced as Tennys Sandgren beat Andreas Haider Maurer 1-6, 6-1, 6-0 while Noah Rubin got the better of Marcos Baghdatis, securing a 7-6 (7-4), 6-4 victory.

Meanwhile, Spanish qualifier Bernabe Zapata Miralles upset Florian Mayer from Germany 6-3, 6-2 while 40-year-old Croat Ivo Karlovic was beaten 6-7 (4-7), 6-4, 7-6 (7-1) by German Peter Gojowczyk.