World number one Dustin Johnson held off the chasing pack in the final round to win the World Golf Championship event in Mexico by one stroke.

The 32-year-old built up what appeared to be an insurmountable four-shot lead on the back nine at Chapultepec Golf Club, only to suffer a wobble to leave the door open for his opponents.

Back-to-back bogeys on the 12th and 13th holes gave Jon Rahm, Tommy Fleetwood and Ross Fisher a chance to put some pressure on Johnson, but he recovered well and got over the line for his fourth success in this competition.

Fleetwood went on to finish in second place thanks to a final-round 66, dropping just the one shot on Sunday and birdying on the final green to see off competition from Rahm, who ended badly with two bogeys across the final three holes.

Fisher also finished in a tie for third, while Rory McIlroy - the midway point leader in Naucalpan - was on 10-under for the competition to end in a tie for seventh.