DORAL, Fla. - A month after he returned from his curious leave of absence, Dustin Johnson was posing with another big trophy.

In a power show Sunday on the Blue Monster, Johnson was flawless on the back nine and blasted two big drives to finish off a 3-under 69 and win the Cadillac Championship for his second World Golf Championship title.

Johnson took advantage of a collapse by J.B. Holmes, who lost a 5-shot lead and closed with a 75 to finish 1 shot behind. Masters champion Bubba Watson opened with four birdies in seven holes to lead by 2 shots, only to make three bogeys in a four-hole stretch on the back nine. He shot 71 and finished 2 shots behind.

Johnson won for the ninth time in his PGA Tour career and moved to No. 6 in the world. It looked as though the 30-year-old Johnson was never gone.

He returned just five weeks ago from a six-month leave of absence to seek professional help for what he described only as personal challenge.

The swagger was back at Trump National Doral, especially on the finishing holes. But when he tapped in for par, it was clear this victory meant more than the others. He walked off with fiancee Paulina Gretzky - the daughter of hockey great Wayne Gretzky - and their son, Tatum, who was born in January.

"I knew I was really good," Johnson said. "I knew there was something I was missing that could make me great. I was working hard on that, and I think it's showing right now. ... It's tough. It feels great. The one definitely, by far, is the best one."

One day after Johnson made a hole-in-one on the par-3 fourth hole, he nearly did it again, missing the cup by an inch. That was his first birdie, and two birdies on the par 5s around the turn drew him closer as Watson slipped.

The pivotal moment came on the par-3 15th, when Johnson rolled in a birdie from just inside 15 feet for a two-shot lead.

He made all the right moves the rest of the way.

Johnson finished at 9-under 279, adding to the WGC title he won in Shanghai at the end of 2013.

Adam Scott (71) and Henrik Stenson (72) tied for fourth, five shots behind.

PGA Tour

RIO GRANDE, Puerto Rico - Alex Cejka won the Puerto Rico Open for his first PGA Tour title, making a 15-foot birdie putt on the first hole of a five-man playoff. He won in his 287th start on the PGA Tour. A four-time European Tour winner, he birdied four of the first six holes and finished with a 3-under 69 in rainy, windy conditions at Trump International-Puerto Rico.

Sam Saunders had a chance to force another playoff hole, but his 8-foot birdie try on the par-5 18th went to the right. Jon Curran, Tim Petrovic and Emiliano Grillo also were in the playoff.

LPGA Tour

SINGAPORE - South Korea's Inbee Park held off top-ranked Lydia Ko and No. 3 Stacy Lewis to win the HSBC Women's Champions for her 13th LPGA Tour title.

The second-ranked Park closed with a 2-under 70 for a 2-stroke victory over Ko.