Johnson wins in Mexico in debut as No. 1 player in the world

Dustin Johnson, of the United States, tees off on the 5th hole during the final round of the Mexico Championship at Chapultepec Golf Club in Mexico City, Sunday, March 5, 2017. All but one of the world's top 50 golfers are contesting the World Golf Championship PGA event, which this year relocated to Mexico City from the Trump National Doral Resort in Florida. (AP Photo/Christian Palma) (The Associated Press)

Dustin Johnson, of the United States, squats down at the 5th hole during the final round of the Mexico Championship at Chapultepec Golf Club in Mexico City, Sunday, March 5, 2017. All but one of the world's top 50 golfers are contesting the World Golf Championship PGA event, which this year relocated to Mexico City from the Trump National Doral Resort in Florida. (AP Photo/Christian Palma) (The Associated Press)

Mexican golf fans hold mariachi motif cutouts depicting from left to right; Jordan Spieth, of the U.S.; Bubba Watson, of the U.S.; Northern Ireland’s Rory McIlroy; Dustin Johnson and Phil Mickelson both of the U.S., during round three of the Mexico Championship at Chapultepec Golf Club in Mexico City, Saturday, March 4, 2017. All but one of the world's top 50 golfers are contesting the World Golf Championship PGA event, which this year relocated to Mexico City from the Trump National Doral Resort in Florida. (AP Photo/Eduardo Verdugo) (The Associated Press)

Dustin Johnson survived a few anxious moments on the back nine by playing mistake-free when it mattered to win the Mexico Championship in his debut as the No. 1 player in the world.

Johnson blasted out of a fairway bunker to the middle of the 18th green to secure a two-putt par for a 3-under 68 and a one-shot victory over Tommy Fleetwood of England.

Johnson became the fifth player to win in his debut at No. 1, and his fourth World Golf Championship title is second on the career list behind Tiger Woods, who won 18 since the series began in 1999.

Fleetwood made a 40-foot birdie putt on the 18th for a 66, which locks up a spot in the Masters.