Croatia's Marin Cilic beat Serbian Janko Tipsarevic 6-3 3-6 6-2 in the St Petersburg Open final on Sunday to claim his first title in nearly two years.
After splitting the first two sets, the fourth seed, who had lost his three previous finals this year, reeled off the last four games of the decider to seal his first victory since February, 2010 in Zagreb.
Tipsarevic, aiming for his second title in as many weeks after triumphing in Moscow having won eight matches in a row, finally ran out of steam against the persistent 23-year-old.
The second seed was broken twice in the final set, conceding defeat after two hours 17 minutes.
"I must say that I felt very tired by the third set," Tipsarevic told reporters.
"However, Marin just played better than me today and fully deserved his victory."
Despite the defeat, the 13-ranked Serbian still has an outside chance of claming one of the last three remaining spots in the season-ending World Tour finals next month.