The world number three from Japan marched to the title with an eagle and seven birdies. His 16-under total of 264 put him five in front of two-time major winner Zach Johnson, who closed with a 68 for 269.
Matsuyama, the first player from Asia to win one of golf’s elite WGC titles, added the Bridgestone trophy to the HSBC Champions crown he claimed in October.
The dominant performance came in the final tune-up event for golf’s best before the last major of the season, the PGA Championship next week at Quail Hollow in North Carolina.
Matsuyama kick-started his round with an eagle at Firestone Country Club’s par-five second, where he chipped in from just off the green.
He capped his round with birdies at 16, 17 and 18 to join Jose Maria Olazabal, Tiger Woods and Sergio Garcia as the only players to shoot 61 on Firestone’s South Course.
“In fact, I played with Tiger four years ago when he shot 61, so I knew 61 was the number today,” Matsuyama said. “I was thinking about that at 16 — I knew if I birdied 16, 17 and 18 I could get there.”
He did — rolling in a six-footer at the last — and will go into the PGA Championship a hot favorite to become the first Japanese man to win a major championship — although he noted that he’s never been particularly successful in the PGA Tour event at Quail Hollow.
“All I can do is my best,” Matsuyama said.
That was certainly good enough on Sunday — although Matsuyama said he had no expectation of such a round after his pre-round practice.
“You wouldn’t have believed how I warmed up this morning,” he said.
“I was not hitting it good on the range. I did hit some good shots, but I was nervous all the way around because I really wasn’t sure of my swing today.”
Nevertheless, his eagle and three birdies saw him leading when he made the turn.
American Charley Hoffman applied some pressure with five birdies in his first 11 holes, but couldn’t maintain his consistency in a 66 that saw him settle for third place on 270.
– ‘Buzz saw’ –
Johnson, who shared the overnight lead with Belgian Thomas Pieters, had three birdies and a bogey in his two-under effort — but parred his way through the last seven holes as Matsuyama consolidated his lead.
Johnson, seeking his first win since the 2015 British Open, was encouraged by his game but said of Matsuyama: “Clearly, we all ran into a buzz saw today.”
Pieters’s one-over 71 was good enough for fourth place on 272.
Northern Ireland star Rory McIlroy carded a 69 to head a group on 273 that also included Scotland’s Russell Knox (68), England’s Paul Casey (67) and Canadian Adam Hadwin (69).
British Open champion Jordan Spieth, who will be pursuing a career Grand Slam at the PGA Championship, closed with a 68 that left him in a group sharing 13th on 276.
“My game improved each and every day, even though my score didn’t reflect it today so I’m really excited going into Quail Hollow,: Spieth said.