Championship WGC-Mexico: Dustin Johnson wins the 20th PGA Tour title

Johnson captured the Mexico title for the third time WGC-Mexico final-leader leaderboard-21 D Johnson (USA); -16 R McIlroy (NI); -11 P Casey (English), I Poulter (Eng), K Aphibarbrat; -10 P Cantlay (USA), S Garcia (Spa), C Smith (Aus) Other selected: -8 T Woods (US); -5 T Fleetwood (T), T Hatton (Eng); -3 D Willett (Eng); -2 L Westwood (Eng); Level R Knox (Sco), Phil Mickelson (US) Full standings

American Dustin Johnson claimed his 20th PGA Tour title with a five-fold victory at the WGC-Mexico Championship.

Six birdies on the back nine were not enough for Rory McIlroy in Northern Ireland to join the number three in the world, who had a head start last night.

McIlroy reduced Johnson's lead to two early in the round but Johnson recorded five birdies in seven holes to score a final-round 66 and finish at 21 under.

The English Paul Casey and Ian Poulter were in third place in eleventh place.

Casey went up 10 places on the leaderboard with a final round of 65, with four birdies on the first six holes. He and Poulter shared third place with Thai Kiradech Aphibarnrat.

Tiger Woods scored a final-round 69 with three birdies to finish in eight under on the shared 10th place.

Johnson, 34, becomes only the fifth player in the last 50 years to win 20 PGA Tour wins before the age of 35, leaving him in the company of only Woods, Phil Mickelson, Johnny Miller and Tom Watson.

Defending champion Mickelson, who opened the game with a 79, rolled into a 12-foot birdied putt on his last hole for a 68 and a level par final total.

Round of the day belonged to Justin Thomas, who scored a nine-under-62.