(Reuters) - A week before defending his PGA Championship title, Justin Thomas showed his game is in fine fettle as he blew away the field for a four-stroke victory at the WGC-Bridgestone Invitational in Akron, Ohio, on Sunday.
Thomas started the final round with a three-shot cushion and was never seriously challenged, a one-under-par 69 more than enough to clinch his ninth PGA Tour title, and his first in a World Golf Championships event.
He finished at 15-under 265 at Firestone, while fellow American Kyle Stanley carded 68 for second place on 11 under.
World number one Dustin Johnson and Dane Thorbjorn Olesen shot 64 and tied for third on 10 under.
Tiger Woods, an eight-times winner at Firestone, finished 15 strokes back after a 73.
The victory was especially special for Thomas, in front of his grandparents.
“They don’t get to come out very often any more. This is my first PGA Tour win with them here, so it’s pretty cool,” he said in a greenside interview.
Grandfather Paul played in the 1960 PGA Championship at Firestone.
Thomas, 25, is the third three-times winner on tour this year, after Dustin Johnson and Bubba Watson.
He held steady on a day when the three players who started closest to the lead all fell apart.
Northern Irishman Rory McIlroy made three straight bogeys around the turn, carded 73 and finished seven shots behind.
Englishman Ian Poulter was similarly profligate. He putted uncharacteristically poorly and was never a factor after four bogeys in the first seven holes.
A 74 left him equal 10th with Australian Jason Day, eight strokes off the pace.
Day crept to 12-under after three straight birdies from the 10th hole, only to drop five shots in the next five holes and shoot 73.
As the big names fell away, Stanley emerged runner-up, no doubt lamenting a four-putt during the second round.
The championship moves to Memphis next year, ending a long run at Firestone.
“I’m glad I finally played well around here, just in time for it to leave,” said Thomas.
Reporting by Andrew Both in Cary, North Carolina; Editing by Clare Fallon and Ken Ferris