Defending champion Fernando Verdasco defeated Russia’s Teymuraz Gabashvili 6-2 6-3 to reach the semi-finals of the US claycourt championships in Houston.
The sixth-seeded Verdasco, from Spain, will face the winner of the late match between top-seeded countryman Feliciano Lopez and eighth-seeded Sam Querrey of the United States.
In the other quarter-finals, American Jack Sock beat fifth-seeded Santiago Giraldo of Colombia 6-4 6-4, and third-seeded Kevin Anderson of South Africa topped seventh-seeded Jeremy Chardy of France 7-5 6-7 (6) 7-6 (3).
The 22-year-old Sock is playing his third tournament of the year after having surgery to repair a torn muscle in his pelvis in December.