The bronze medallist from the Paris Olympics held onto a comfortable lead through nine holes, but then his challenge appeared to be eroding when he dropped four strokes in a row, including a dismal tee shot into the water on the fourteenth.
Viktor Hovland seized the lead on the 17th hole after Matsuyama staggered, but he recovered to take the lead by one stroke with one hole remaining.
At the first leg of the PGA Tour’s season-ending play-offs, an outstanding second shot on the par-four 18th hole hit the green, and a putt for birdie sealed the victory by two.
Matsuyama, 32, was competing at TPC Southwind without his customary caddie following his team’s robbery during a post-Olympic stopover in London.
Hovland, the reigning champion from Norway, shared for second place on 15 under par with world no. 2 Xander Schauffele from the United States.
The top 70 in the FedEx Cup points standings competed in this tournament, with the top 50 moving on to the BMW Championship in Colorado. American world number one Scottie Scheffler finished fourth on 14 under.
The top 50 finishers advance to Colorado and are qualified for all eight of the 2025 PGA Tour flagship tournaments.
