This time there wasn't a wicked hook wedge from dense forest but "Bubba Golf" still returned to Augusta National as Bubba Watson claimed his second green jacket in three years.

In 2012 it took a stunning but unconventional hooking wedge shot from pine straw on the second play-off hole to claim his maiden Masters, while the repeat effort was almost a stroll in the park.

Watson became the 17th player to clinch at least two green jackets with a final round three-under 69 and an eight-under 280 total, finishing three clear of 20-year-old Jordan Spieth (72) and Swede Jonas Blixt (71), who tied second at five under.

Fifty-year-old Spaniard Miguel Angel Jimenez (71) was fourth at four under, with Americans Matt Kuchar (74) and Rickie Fowler (73) a shot further back.

"It's overwhelming to win twice, to be with the great names," Watson said.

"A small-town guy named Bubba now has two green jackets, it's pretty wild."

What is wild is Watson's unconventional, never-had-a-lesson golf swing.

On Sunday the traditional back nine roars may have been absent as no-one in the field made a charge, but Watson still had everyone shaking their heads in disbelief.

With four holes to play Watson held a three-shot buffer, only to drive his ball into the trees on the par five 15th.

Traditional wisdom was to punch out, lay-up then hit a wedge over the water to protect the lead.

But Watson doesn't understand traditional golf.

Instead he figured out the 181 yards to the front of the green, enough to carry water, choked down on a six-iron, found a gap in the limbs, and blasted away, cutting the ball to the back of the green.

A ball in the water could have produced a dropped shot and if Spieth found a birdie on the same hole it would have been game on.

Instead, it was game over.

But despite joining an elite class of multiple major winners and moving to world No 4, Watson humbly batted away talk of becoming one of the greats.

"I just got lucky enough to have two green jackets," Watson said.

"I'm just trying to keep my tour card every year and if people say that I'm a good player, that's great.

"But I'm not trying to play golf for everybody to tell me how great I am or I'm one of the greats of the game. I play golf because I love it.

"The game has brought me everything that I've ever owned in my life."

Earlier, after seven holes of the final round, the 20-year-old Spieth seemed destined to don green as the youngest ever champion.

He held a two-shot lead and looked in control.

But bogeys on the eighth and ninth as Watson made back-to-back birdies turned the tournament on its head with a four-shot swing, leaving him two behind.

"I got off to kind of a dream start for Sunday at Augusta. It's just so hard to play the first seven holes well out here, and I was three under," Spieth said.

"If you told me that when I woke up this morning, I would have thought it would be difficult for me to not win this golf tournament." AAP