Dustin Johnson consolidated his position at the top of the world rankings as he held off a strong European challenge to clinch a one-shot victory at the WGC-Mexico Championship on Sunday.
Johnson was four shots clear of the field early on the back nine at Club de Golf Chapultepec in Naucalpan before back-to-back bogeys opened the door for the likes of Jon Rahm, Tommy Fleetwood and Ross Fisher, but the American held his nerve down the stretch to collect his fourth World Golf Championship title.
Fleetwood continued his impressive start to the year as he won the race for second by holing a huge putt for birdie on the final green, while Rahm was left to rue a poor finish as he three-putted the 16th and 17th greens to slip to 12 under alongside Fisher.
Rory McIlroy could not get anything going on the greens and stuttered to a disappointing 71 to finish four shots off the pace, while Lee Westwood was only one behind before tumbling down the leaderboard with four double-bogeys in an expensive six-hole stretch around the turn.
But the tournament belonged to Johnson, who celebrated his first start as world No 1 with his 16th career victory just a fortnight after cruising to a five-shot win at the Genesis Open to dethrone Jason Day at the top of the rankings.
Johnson picked up an early birdie at the second and got up-and-down for another at the long sixth before nailing a 30-foot putt for a brilliant three at the eighth hole.
The US Open champion converted a solid wedge to eight feet to cap an outward 31, but he faltered when he three-putted the 12th and then bunkered his tee shot to the par-three 13th and failed to salvage his par.
But Johnson got one shot back at the long 15th to remain tied for the lead with Rahm, who buckled under the pressure of being in contention in his maiden WGC appearance.
The in-form Spaniard reeled in Johnson when he drilled a stunning 260-yard second to 15 feet at the 11th and rolled in the eagle chance, and he drained a 35-footer for birdie at 14 and made a good birdie-four at the next before three-putting from 70 and 60 feet on the next two greens.
Fleetwood then kept the pressure on the leader when he followed birdies at 11, 12 and 15 with a thrilling 40-foot putt for a closing three which rounded off a 66 and gave him the clubhouse lead on 13 under.
But Johnson safely negotiated the 16th and 17th in par before finding a fairway bunker with his final tee-shot of the day, although he atoned with a well-struck wedge from the sand which found the green and left him with two putts for the win from inside 20 feet.
Fisher had earlier set the target at 12 under when he birdied the final three holes to return a superb 65, the joint-low round of the day, earning him a share of third with the disconsolate Rahm.
Ryder Cup sensation Thomas Pieters made the most significant early move when he birdied three of the opening four holes, but he could not maintain his challenge and a bogey at the last saw him slide to 11 under with overnight leader Justin Thomas, whose hopes effectively ended when he double-bogeyed the seventh and bogeyed eight.
McIlroy offset two birdies with a pair of bogeys and endured a number of near-misses with the putter, and a frustrating 71 left him at 10 under alongside Phil Mickelson (71) and the fast-finishing Brandt Snedeker, who had five back-nine birdies in a 65 that was only slightly tarnished by a bogey at 18.
Tyrrell Hatton's "American adventure" continued as a 70 earned him another top-10 finish on nine under, while Westwood's torrid day added up to a 78 - two under for the tournament and way down the leaderboard in a tie for 28th.