The 26-year-old entered Round 4 at Medinah Country Club with a whopping six-shot lead after firing a course-record 61 on Saturday.
Cantlay managed to make things interesting with four straight birdies midway through the round Sunday, but Thomas weathered the storm and rattled off four birdies in his final eight holes to take home the trophy.
Here's how the top of the leaderboard finished:
|Place||Player||To Par||R4 Score|
With his 10th career PGA Tour victory, Thomas joins Tiger Woods, Jack Nicklaus, Jordan Spieth, and Rory McIlroy as the only players to collect double-digit wins, including a major, before age 27 in the last 75 years, according to the 15th Club's Justin Ray.
Thomas will enter the Tour Championship as the No. 1 seed in the FedEx Cup points list. Under the new format, he will start next week's tournament at 10-under par, two shots ahead of the second-seeded Cantlay.
Matsuyama posted his second 9-under 63 of the week to climb into third, while Finau - who played in the final group with Thomas and Cantlay - shot 69 to take fourth.