Janko Tipsarevic claimed his maiden ATP Tour clay-court title at the Mercedes Cup with a three-set defeat of Juan Monaco.
The Croatian was pushed all the way by his Argentinian opponent before finally prevailing 6-4 5-7 6-3 to record his second victory in their four meetings.
It looked as though Tipsarevic, having won the first set, would cruise through the second when he established a 4-0 lead.
But Monaco showed plenty of grit to win five games on the trot and eventually claim it on his first set point.
The decider was hit by a rain delay but it only stalled Tipsarevic's victory charge as, from 3-3, he won three successive games to clinch the crown in two hours and 36 minutes.
Tipsarevic said he was surprised by his triumph.
"I honestly still don't believe I won the title, considering that in almost every match I was hanging to lose.
"There were a lot of ups and downs. I think my mental attitude was the key for me - fighting from the first to the very last point. I think that is one of the reasons why I managed to win the title."
The Serb played at last year's ATP World Tour Finals in London as an alternative but admits this year he is determined to qulaify as of right.
"I want to play London at the end of the year, I really do," he added.
"Last year, my goal was to reach the top 20. Instead of that I reached the top 10 and was reserve in London. You don't get to play with the top eight unless you fight for every point."