Golf: Spieth the master at just 21

Bubba Watson helps Jordan Spieth put on the green jacket. Photo / AP

Last year’s runner-up leads from start to finish in a record-breaking blitz of birdies at Augusta.

American Jordan Spieth has cemented his place as the next big thing in golf, becoming the second-youngest US Masters champion after dominating the field by going wire-to-wire to win by four shots.

Invoking memories of Tiger Woods' breakout performance in 1997, the 21-year-old Texan will jump to world No2 behind only Rory McIlroy after shooting a final round two-under 70 to win at a tournament record-equalling 18-under 270.

Former US Open champion Justin Rose (70) tied for second with five-times major champion Phil Mickelson (69).

A birdie on the 15th hole sent Spieth to 19-under, the first time the score has been reached in Masters history, but he dropped back a shot on the 18th and tied Woods' Masters record set in his first win in 1997 when he was just a few months younger.

He broke the 54-hole tournament record shared by Woods (1997) and Floyd (1976) on yesterday, having set a 36-hole record a day earlier.

Spieth, the reigning Australian Open champion, showed composure way beyond his years becoming only the fifth wire-to-wire winner, joining Craig Wood in 1941, Arnold Palmer in 1960, Jack Nicklaus in 1972 and Raymond Floyd in 1976.

"It's the most incredible week of my life," said Spieth. "It's a dream come true. I'm still kind of in shock a little bit."

He added: "It was very nerve-wracking today. With two major champions right behind me, I couldn't let up."

Rose got within three shots a few times on the front nine while Mickelson was within four on the front nine, but neither could make further inroads.

Spieth's 28 birdies eclipsed the most in a single Masters tournament, taking over from Mickelson's 25 in 2001 and came just a year after finishing as runner-up to Bubba Watson on debut.

McIlroy closed with a 66 to finish at 12-under in fourth as he chased the career grand slam.

He was one clear of 23-year-old Japanese young gun Hideki Matsuyama who also shot 66.

Woods could only muster a 73 yesterday, leaving the 14-time major winner in a tie for 17th.

Australia had its worst Masters performance since 2001, with Jason Day leading the way at one-under-287 in a tie for 28th.

Day dropped a disappointing 75 on Sunday but still bested 2013 champion Adam Scott who posted a 74 to finish one-over, thanks mainly to a quadruple-bogey seven on the picturesque par-three 12th when he found water twice.

"Overall a pretty disappointing week, really," Day said.

- AAP