World number three Stan Wawrinka beat Roberto Bautista Agut 7-6(8) 6-2 on Saturday and will play Alexander Zverev in the St. Petersburg Open final.
The Swiss top seed, playing his first tournament since beating Novak Djokovic to win the U.S. Open title, wore down the Spanish fourth seed Bautista Agut after a tight first set.
German Zverev, the fifth seed, upset third seed Tomas Berdych of the Czech Republic 6-4 6-4.
The 19-year-old, who has Russian roots, will be hoping it is third time lucky in his third ATP final after losing the previous two.
