For the second time in three years, Dustin Johnson is the WGC-Mexico Championship winner.
Johnson shot a five-under score of 66 in Sunday's fourth round, finishing at 21 under overall for a five-stroke win over Rory McIlroy. Paul Casey, Ian Poulter and Kiradech Aphibarnrat rounded out the top five.
His five-stroke win is the largest in this event since 2006, when it was called the WGC-American Express Championship and was played in England. Tiger Woods won the 2006 event by eight strokes.
Since it was relocated to Chapultepec, Mexico, in 2017, the event's first two championships were decided by a combined one stroke. Johnson won the 2017 event by a stroke before Phil Mickelson won last year in a playoff.
There would be no such intrigue this time around.
Johnson began the day with a four-stroke lead over McIlroy and never looked back. He started slow and went one over through his first five holes, but McIlroy did not capitalize to make it close. Instead, McIlroy carded a pair of bogeys on his first six holes and made the turn at one over before righting the ship to shoot a final-round 67. He birdied six of seven holes from Nos. 11-17 before bogeying No. 18.
By the time McIlroy started to turn his day around, so had Johnson. He birdied the par-five sixth to move back to even on the day and started the back nine with consecutive birdies. He smoked a 374-yard drive onto the fairway on the 10th hole before hitting his approach within four feet. He topped that on the next hole with a 404-yard fairway drive for an easy birdie on the massive par-five 11th.
Accuracy off the tee was not Johnson's strength for most of Sunday, but he made up for it by being consistently long. His 343.5-yard average drive was 13 yards better than his already stellar mark over the first three rounds.
The win is Johnson's 20th on the PGA Tour and first since last July's RBC Canadian Open. He will move back into the No. 2 spot on the world golf rankings next week, encroaching on No. 1 Justin Rose, who did not play in this tournament.
Current No. 2 Brooks Koepka finished in a tie for 27th at three under overall.
Tiger Woods finished with his first top 10 of the calendar year, shooting a two-under 69 to finish eight under overall in a tie for 10th. Woods has yet to truly contend in a tournament this season, but he also has finished no worse than 20th.
Mickelson's title defense ended after a 79 on Thursday, but he managed to battle back to finish the tournament at even par after shooting a three-under 68 on Sunday.