Justin Thomas of the US celebrates on the 18th green after winning during the final round of the BMW Championship on Sunday in Medinah, Illinois. Photo: VCG

Justin Thomas captured his 10th career US PGA title on Sunday, holding off fellow American Patrick Cantlay down the back nine to win the BMW Championship in record-smashing fashion.

The 2017 PGA Championship winner seized his first triumph since last year's WGC Bridgestone Invitational, defeating Cantlay by three strokes, and claimed the top spot in the US PGA playoff point standings entering this week's season-ending Tour Championship.

"I was really nervous today," said Thomas, who began the day with a six-stroke advantage. "It's hard to play with the lead. I was enjoying it though.

"I forgot how hard it is to win. That's why it has taken this long. I've been working hard to get back to it and it feels great."

Thomas fired a four-under-par 68 to finish 72 holes at Medinah on 25-­under 263, shattering the former mark of 23-under at the 116-year-old event shared by American Dustin Johnson and Australian Marc Leishman.

Thomas birdied four of the last eight holes at the suburban Chicago layout to fend off Cantlay, who closed with birdies on four of the last six holes and nine birdies in all.

"I just stayed patient," Thomas said. "Patrick made that very interesting. I hit the ball so bad to start the day. I couldn't hit a fairway. That was a hard start."

After seeing his lead shrink to two shots, Thomas landed his approach two feet from the cup at 11 to set up a birdie and surged to the finish.

"That birdie on 11 was huge," he said. "It kind of propelled me."

Thomas, who won the 2017 FedEx Cup playoff crown, made himself the player to beat in this week's Tour Championship at East Lake in Atlanta.

Thomas will start at 10 under par with a two-stroke lead over second-place point producer Cantlay in this week's event under a new points format that ensures the tournament winner will capture the playoff crown.

For Thomas, that means sitting on a lead for four days before he swings a club.

"I'm just going to go out there and try and play as well as I can," Thomas said. "I'm going to try not to look at the leaderboard. I've got to drive the ball a whole lot better than I did this week."

Japan's Hideki Matsuyama finished third on 268 after his second 63 in three days, a third-round 73 spoiling his title bid. He needed only 20 putts Sunday.

American Tony Finau finished fourth on 270, one shot ahead of countryman Brandt Snedeker and Spain's Jon Rahm.

But Finau's 69 was not enough for him to overtake Bryson DeChambeau for the final automatic berth on the US team for December's Presidents Cup in Australia, qualifying for which ended on Sunday.

Players who moved into the final 30-man Tour Championship field by their results at Medinah included Matsuyama, 2009 US Open winner Lucas Glover and fellow American Jason Kokrak.

Tiger Woods, last year's Tour Championship winner, and Jordan Spieth were among those unable to claw their way back into the top-30 in order to qualify for East Lake.