Juan Martin del Potro boosted his hopes of qualifying for the ATP Finals and delayed confirmation of Grigor Dimitrov's likely qualification by beating the Bulgarian in straight sets to retain the Stockholm Open title.

Victory for Dimitrov in the final would have been enough to assure the No.1 seed of a place in the season-ending showpiece, but he will now have to wait at least another week to book his place in London.

Del Potro charged to a 6-4 6-2 victory and is now up to 14th in Race to London himself, with increased hope of catching Pablo Carreno Busta, the man occupying the final qualifying slot.

Two of the players between Del Potro and Carreno Busta in the standings — Novak Djokovic and Andy Murray — are sidelined through injury.

"I played the best match of the week against Grigor today. Unlucky for that, sorry Grigor," Del Potro said during the on-court presentation.

"It's amazing to come back and hold this big trophy. And hopefully I can come next year as well. I love to be in Stockholm."

A solitary break was all Del Potro required to forge ahead the first set, which he brought to a close with an ace.

Dimitrov, who came into the match boasting a perfect record from three previous finals this year, proved unable to fight back as his rival hurried to victory thereafter.

Del Potro now has 20 titles on the ATP World Tour, his last success having come in this event 12 months ago.