Dustin Johnson is making golf sound as easy as he makes it look.

There was nothing fancy about the way he went about his work Sunday in the Bridgestone Invitational, where he rallied from a three-shot deficit against the world's No. 1 player to win in his first start since capturing his first major at the U.S. Open.

He drives it great. His wedge game has been his biggest improvement. He finally is making some putts.

Is it really that simple?

"I mean, yeah," Johnson replied.

Late last year, he decided to abandon his natural draw off the tee and switch to a fade because he thought he would hit more fairways.

"I got tired of hitting hooks," he said.

When asked if it was his choice or a recommendation from his coaches, Johnson said he wanted to make the change and his coaches didn't really care which shape he hit the driver "as long as I hit it straight."

So was the change in his swing or the way he sets up to the ball?

"You'll have to ask my coach," he said.

It's been a winning combination, especially in his last two tournaments. Two weeks ago at Oakmont, he overcame a four-shot deficit to win the U.S. Open, even though he wasn't sure of his score over the final two hours because the USGA couldn't make up its mind whether to assess a penalty for a ball moving.

On Sunday, it took him 16 holes to wipe out a three-shot deficit against Jason Day, and then Johnson took over from there.

He blasted a 9-iron out of the deep rough to 15 feet and made birdie to take the lead for the first time all week, right about the time Day was making an utter mess of the par-5 16th hole.

Day tried to play it safe off the tee on the 655-yard hole, knowing he couldn't get home in two, and instead hooked his tee shot behind two thick fir trees. He blasted through branches and across the fairway, and then tried to get it just left of the green with a punch shot that wasn't hit hard enough, or far enough left. It rolled into the side of the water, leading to double bogey.

"Sometimes you take risks and it doesn't pay off," said Day, who didn't hit a green on his last six holes and closed with a 72.

Johnson made six birdies in his round of 4-under 66 and wound up winning by one shot over Scott Piercy, who made birdie on the final hole for a 70. It was the second straight time Piercy was runner-up to Johnson, and there was some consolation that they were at the U.S. Open and a World Golf Championship.

"We all know how good DJ is, and he's shown it the last weeks," Piercy said. "To be nipping at his heels makes me feel good. ... We want to win being out there, and knowing that I came as close as I did, not having my best stuff is a positive, as well."

Day tied for third with Jordan Spieth, Matt Kuchar and Kevin Chappell.

Only nine players finished under par, the fewest number at Firestone since Tiger Woods was the only player under par in 2007. Johnson finished at 6-under 274, the highest winning score since Woods in 2005.

And there was one other connection to Woods — they now are the only two players to win three of the four World Golf Championships. Johnson won the Cadillac Championship at Doral last year and the HSBC Champions in Shanghai in 2013.

Johnson narrowly moved past Spieth to a career-best No. 2 in the world. He moved to the top of the FedEx Cup, and is No. 1 on the money list with over $6.5 million.

And he can't wait to get to the British Open at Royal Troon in two weeks.

"It's the first time I've won two tournaments in a row," Johnson said. "I mean, that's big. I'm excited and looking forward to going over to the British with the golf game in good form."

To explain how he could go from winless over 15 months to looking as though he can't be beat is to return to Johnson's world of simplicity.

It's all about putting.

There is some truth to that. He has only three finishes outside the top 20 in the last year on the PGA Tour.

"I feel like my game is where it has been all year," he said. "I feel like I've been playing really solid all year. I've been driving it great. I've been wedging it good. It's just I haven't been putting quite as well as I'd like to. And the last couple weeks, I've just putted a little bit better. And the game shows it."

Maybe it's really that simple.