Chilean fourth seed Fernando Gonzalez edged a hard-fought final 6-7 (8-10) 6-3 7-5 6-4 against Cypriot qualifier Marcos Baghdatis at the Swiss Indoors.
Baghdatis, 20, showed no signs of nerves in his first Tour final in Basel but was hampered by a thigh injury and came up short after the opening set.
Gonzalez's win in just under three hours boosts his chances of qualifying for the season-ending Masters Cup.
But he must win the Paris Bercy next week to be sure of a place in Shanghai.
Baghdatis had been looking to become the first qualifier in more than a year to win an ATP event - and the first player from his country to win a title on the men's Tour.
And the world number 85 proved more than equal to his opponent, 17th in the global rankings, during the opening stages.
But his long week - in which he upset eighth-seeded Tommy Haas and second-seeded David Nalbandian - appeared to catch up with him as the match wore on and the hard-hitting Gonzalez finally broke ahead late in the second set and early in the third.
After calling for treatment on his left thigh, Baghdatis somehow managed to get back on level terms before Gonzalez finally took control by breaking again.
The Chilean seized the decisive break in the first game of the fourth set.
The victory was Gonzalez's third of the season - he triumphed earlier in the year in Auckland and Amersfort - and the seventh Tour title of his career.
It also saw him go one better than 2002, when he lost the Basel final to Argentine Nalbandian.
Afterwards Gonzalez praised Baghdatis, who had also reached the final of the men's doubles.
"I was lucky, my tennis has been unbelievable," he said.
"I want to congratulate my opponent. He played two more matches than me and maybe he was a little more tired."