Two shots behind with four holes to play, Patric Reed ran off three straight birdies to overtake a faltering Bryson DeChambeau, closing with a 4-under 67 for his second World Golf Championships title.
Reed made it interesting in the end with a wild tee shot into the trees on the 18th hole, forcing him to chip back to the fairway. He had to two-putt from 35 feet for eighth victory of his PGA Tour career.
He one-putted 45 times over 72 holes, an astounding performance on the poa greens of Chapultepec. The birdies at the end might not have mattered without par putts from 10 feet on the 11th and 8 feet on the 13th as DeChambeau was starting to pull away.
In a wild final round in which five players had a share of the lead — four were tied heading for the back nine — DeChambeau appeared to seize control with five birdies in a six-hole stretch starting at No. 9.
Everyone around him faltered — Justin Thomas, Rory McIlroy, Jon Rahm, Erik van Rooyen — everyone but Reed, who played bogey-free until he only needed a bogey to win.
DeChambeau missed two good scoring chances on the 15th and 16th, and then he three-putted from 65 feet on the par-3 17th to fall into a tie. Reed seized on the moment. Blocked by the edge of the trees left of the 16th fairway, he hammered a hook with a gap wedge that rolled around the ridge and fed down the slope to 3 feet.
Reed never flinched with so much going on around him, on and off the golf course.
He finished at 18-under 266 and moved to No. 8 in the world.
Rahm had a chance to reach No. 1 in the world with a victory, depending on how McIlroy finished. It was a moot point when the Spaniard took bogey on the par-5 11th and dropped another shot on the 14th with a short iron that went just over the back of the green.
McIlroy was within one shot until going nine straight holes without a birdie.
Thomas lost the lead when he hit into the water on the par-3 seventh, and then made another bogey on the next hole. He then had to play a left-handed shot on the 10th on his way to a double bogey. He shot 73.
