France's Alize Cornet won her fourth career title on Sunday when she saved a match point on her way to a 7-6 (7/3), 5-7, 7-5 victory over Italy's Camila Giorgi in the Katowice final.
Cornet, the world 22, added the Poland title to trophies at Budapest in 2008, Bad Gastein in 2012 and Strasbourg last year.
The 24-year-old had knocked out world number three Agnieszka Radwanska in the semi-finals.
"What a match. It was definitely a huge fight, which is what I expected, and I had to save a match point to win the title, so it feels very special," said Cornet who faced match point at 4-5 in the decider.
"I gave everything I had. I'm so happy I could win here at this beautiful tournament in Katowice."
Sunday's three-hour, 11-minute match is the fifth-longest match of the year and the longest WTA final since the three-hour, 12-minute Osaka final in October 2012.
Giorgi was contesting her first WTA final, having never been to a quarter-final prior to this week.