Fourth-seeded Santiago Giraldo of Colombia beat Russian Andrey Rublev 6-4, 1-6, 6-3 to reach the quarterfinals of the inaugural Istanbul Open on Wednesday, while Spaniard Daniel Gimeno-Traver upset sixth-seeded Kazakh Mikhail Kukushkin 6-3, 6-3 to set up a potential match against Roger Federer.

The second-ranked Federer was playing his second-round match later Wednesday against Finnish veteran Jarkko Nieminen.

Giraldo struggled at times against Rublev, with both players dropping their serve three times. Although Rublev had more aces — 7 compared to 3 — Giraldo won more of his first-service points.

He next plays eighth-seeded Diego Schwartzman of Argentina, who took less than one hour to beat Austrian Jurgen Melzer 6-0, 6-2.

Gimeno-Traver dropped serve once, but otherwise was hardly troubled, using five aces and breaking his opponent's serve four times.