Juan Martin del Potro defeated world No. 1 Roger Federer in a three-set thriller in the final of the Swiss Indoors in Basel on Sunday.
Five-time champion Federer failed to break del Potro's serve once on his way to a 6-4, (5)6-7, 7-6(3) defeat in the Swiss star's ninth Basel final.
It was the first time this year that del Potro had beaten Federer in seven meetings.
The Argentinian player, 24, claimed his fourth title of the year and €338,000.
Both players have already qualified for the Tour Finals that will be held London next month.