Dustin Johnson didn’t take long to validate his climb to No. 1 in the Official World Golf Rankings.
Johnson, who won the Genesis Open in his last start to earn the top spot, closed with a 3-under-par 68 and held on for a one-stroke victory over Tommy Fleetwood of England in the WGC-Mexico Championship at Club de Golf Chapultepec in Mexico City.
“It means a lot, obviously,” said DJ, who claimed the 14th victory of his PGA Tour career. “There’s obviously more pressure being No. 1, but I came out and played well. I hit the ball well, but I didn’t make a lot of putts.
“I don’t think I putted badly, but the ball just didn’t go in the hole. Maybe my reads weren’t as good as they could have been. I thought I made some good strokes, but even though I didn’t putt so well, it was good enough to win by one.
“I knew I was tied and had to play well down the stretch to win. I’m proud of the way I played.”
Johnson, who made four birdies on the front nine and built a four-stroke lead, made bogeys on the 12th and 13th holes before a final birdie at No. 15 took him to a winning score of 14-under 270.
DJ became the fifth player to win his first tournament since taking the No. 1 ranking, joining Ian Woosnam of Wales (1991 Masters), David Duval (1999 BellSouth Classic), Vijay Singh (RBC Canadian Open) and Adam Scott (2014 Crowne Plaza Invitational at Colonial).
Johnson, who also won the 2013 WGC-HSBC Champions, the 2015 WGC-Cadillac Championship and the 2016 WGC-Bridgestone Invitational, won for the fourth time in the World Golf Championships, behind only Tiger Woods’s 18 titles.
Fleetwood, who has won twice on the European Tour, sank a 39-foot birdie putt on the 18th hole to cap a second straight 66 and posted his best finish in six starts in the World Golf Championships.
Rookie Jon Rahm of Spain, who claimed his first pro victory in February in the Farmers Insurance Open at Torrey Pines, sank a 14-foot eagle putt on the 11th hole and added birdies on Nos. 14 and 15 to tie Johnson for the lead.
However, Rahm made bogeys at Nos. 16 and 17 in a 68 that left him two shots backs in a tie for third with Ross Fisher of England, who birdied the last three holes in a 65.
Justin Thomas, the 54-hole leader who has won three times this season, stumbled to a 72 and was three back in a tie for fifth with Thomas Pieters of Belgium, who carded a second straight 68.
Phil Mickelson, who struggled with his ball striking for a second straight day, shot 71 to wind up another stroke back in a tie for seventh with Brandt Snedeker, who totaled 65, and third-ranked Rory McIlroy of Northern Ireland, who finished with a 71 in his first event in seven week after overcoming a rib injury.
Tyrrell Hatton of England was 10th after a 70, while sixth-ranked Jordan Spieth posted a 71 to finish in a tie for 12th that included Sergio Garcia of Spain, who also had a 71.
Rickie Fowler of Murrieta carded a 67 to tie for 16th, fifth-ranked Hideki Matsuyama of Japan tied for 25th after a 71, and defending champion Adam Scott of Australia recorded a second straight 68 to tie for 45th.