Top seed Mikhail Youzhny progressed to the semi-finals of the St Petersburg Open with a straight-sets victory over Guillermo Garcia-Lopez.
Youzhny overcame the seventh-seeded Spaniard 6-4 0-6 6-3 in two hours and six minutes on Friday.
The Russian, who claimed the 2004 title, took the opening set but faltered in the second, winning just five points on his serve.
Youzhny recovered from an early break in the final set to secure his first win in five attempts against Garcia-Lopez.
The world number 29 will meet third seed Martin Klizan for a place in the final after the Slovakian downed Ricardas Berankis of Lithuania 6-3 6-2.
World number 93 Daniel Gimeno-Traver defeated Italy's Flavio Cipolla 6-2 7-5 to earn his first semi-final appearance in more than two years.
The Spaniard converted seven of his 10 break point opportunities as he reached the final four of a tournament for the first time since July 2010, when he fell to Nicolas Almagro at the Gstaad Open.
Gimeno-Traver, who is yet to contest an ATP Tour final, will face fourth-seeded Italian Fabio Fognini.
Fognini booked a spot in the semi-finals with a 6-4 7-6 (7-1) triumph over Spain's Roberto Bautista-Agut in one hour and 41 minutes.