Dustin Johnson Back to Golf, Back to Winning - ABC News

The six-month break from the game raised more questions about Dustin Johnson's personal life than his golf. He said it gave him time to work on a little of each, and he delivered answers to both Sunday at the Cadillac Championship.

Johnson made up a five-shot deficit on J.B. Holmes and had a one-shot lead as he stood on the 18th tee at Trump National Doral, among the most daunting shots in golf. He produced his best drive all week, a monster shot that cleared the corner of the water and sent him to a routine par and a victory that never felt better.

He left the green holding his 7-week-old son, Tatum, with fiancee Paulina Gretzky at his side.

"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. I'm so excited right now, I can't hardly talk. It feels great. This one definitely, by far, is the best one."

Johnson holed two big par putts from 20 feet and 10 feet that put him in the lead on a back nine of survival, seized control with a 15-foot birdie putt on the 15th hole and powered home to a 3-under 69 and a one-shot victory over Holmes.

It was his ninth career win, and second World Golf Championship title, and it returned him to the elite in golf at No. 7 in the world.

Still lingering are questions about his curious six-month leave he announced in August that caused him to miss the final major and the Ryder Cup. He said it was to seek professional help for "personal challenges." Golf.com reported he had failed a second cocaine test, the first one in 2012 when he missed the Masters for what he called a back injury from lifting a jet ski from the water.

Johnson said again he has never failed a drug test. He said he was done talking about it in an interview with The Associated Press in January, and when pressed anew about why he had not been more forthcoming with answers, Johnson replied, "Because it's personal and frankly, it's not really anybody's business."

In an interview before he returned, Johnson said he was handling stress through too much partying. He said he spent time with his future father-in-law â€" hockey great Wayne Gretzky â€" and a person he described as a life coach.

There are no questions about his golf. The swagger was back, especially as he closed in on a victory.

Johnson won in his fifth start back â€" Johnson lost in a playoff at Riviera and tied for fourth at Pebble Beach â€" and did what few others could manage at Doral. He never made worse than a bogey all week, and he didn't have a single three-putt.

"If he's won nine times out here, you're pretty good," Holmes said after making only one birdie in a round of 75.

Holmes lost his five-shot lead quickly, thanks to three bogeys in his opening five holes, and Masters champion Bubba Watson opening with four birdies in seven holes. Watson went from a five-shot deficit to a two-shot lead on the front nine, but three bogeys in a four-hole stretch on the back nine â€" two from bunkers, one from the palm trees â€" ended his big run. He closed with a 71 and finished two shots behind.

"A couple of shots, just missed the fairway by a few feet. Missed the green by a few feet. That's what this golf course does," Watson said. "If you're just off, it can get to you real fast."