Romania's Sorana Cirstea said she "didn't expect" to win the Istanbul claycourt tournament on Sunday, her second career title coming 13 years after her first.
The 31-year-old Romanian defeated top-seeded Elise Mertens of Belgium 6-1, 7-6 (7/3) in the final having not dropped a set all week.
Cirstea, ranked at 67 in the world, captured her maiden title at Tashkent in 2008.
Sunday was her fifth final, having made her maiden championship match as a 17-year-old qualifier at Budapest 2007.
"I'm very, very happy for this trophy," Cirstea said at the winner's ceremony.
"I did not expect it, to be honest, so probably I'm twice as glad!"
Mertens, the world number 17, was playing in her 10th career final, and second of the season after her victory at the Gippsland Trophy in February.
Cirstea is now 3-0 in her career against Mertens after breaking serve five times in windy and chilly conditions.
She wrapped up the first set in just 28 minutes but then had to claw her way back from 2-5 down in the second.