The 35-year-old was embraced by his wife and their son on the 18th green, he and Angie having adopted Caleb just days before his victory over Louis Oosthuizen in a play-off two years ago.

Spieth was looking to eclipse Tiger Woods as the youngest ever Masters champion and the 20-year-old held a two-shot lead after seven holes, aided by holing a bunker shot on the fourth.

But that two-shot lead became a two-shot deficit in the space of two holes and with no-one able to mount a challenge, Watson held his nerve on the closing stretch to ensure a sixth Masters victory by a left-hander since 2003.

European hopes of a first winner since Jose Maria Olazabal in 1999 had been high, but Jimenez - also looking to become golf's oldest Major champion - paid the price for a front nine of 38, while Lee Westwood was never in contention after playing the first four holes in three over.

Rory McIlroy's best Masters finish was little consolation for a frustrating week which also saw the former world number one outscored by his marker in the third round, the 24-year-old joint eighth with 56-year-old two-time champion Bernhard Langer.

The previous three winners had come from outside the last group, but the final round was largely a duel between Spieth and Watson, who had won just once in seven attempts when in the lead after 54 holes.

Spieth, who only turned professional in December 2012, hit poor tee shots on the opening two holes but made par on the first and then holed from 15 feet for birdie on the par-five second.

The par-three fourth hole had already cost Westwood a double bogey and also saw Matt Kuchar four-putt for a double bogey when tied for the lead, but Spieth had no such worries as he holed out from a greenside bunker for an unlikely birdie.

Watson had bogeyed the third and was briefly three behind, but the left-hander then calmly holed from five feet for his own birdie to close the gap.

Spieth was unable to conjure up more magic from a greenside bunker on the fifth, but a brilliant tee shot to the sixth set up another short birdie putt which he converted after Watson had holed from 10 feet for a two.

Another birdie on the seventh took Spieth to eight-under-par and two shots clear, but that turned into a two-shot deficit just 20 minutes later.

A three-putt bogey on the eighth was followed by another on the ninth when his approach span back off the green, while Watson got up and down from over the eighth green and then holed from 12 feet on the ninth.

Watson dropped a shot on the 10th - where he won his play-off with Oosthuizen - but then saw Spieth find the water in front of the green on the 12th to fall two behind again.

Length off the tee has often been a major advantage for Watson and a drive of more than 360 yards down the 13th set the 35-year-old up for a birdie to stretch his lead to three.

And when he holed a testing putt for par on the 17th to maintain that cushion, the energetic fist pump told its own story.

Westwood's record winless streak in majors stretched to 64 and the 40-year-old said: "It's a little bit disappointing.

"I needed to get a quick start but was three over after four and that's not ideal. I had a chance, although Bubba is eight under at the moment, but seventh is my best result this year and the work I am doing with my coach is taking me in the right direction. The Masters probably came a couple of weeks too early."

McIlroy's previous best finish at Augusta was joint 15th in 2011, when he led by four shots going into the final round before collapsing to a closing 80.

But the 24-year-old was again left wondering what might have been if not for a second round of 77 and a failure to convert enough birdie chances, especially on the par fives.

"It's been a frustrating week, because I felt like from tee to green I played as good as the leaders," McIlroy said after his 69. "I don't think I've ever played as good tee to green around this course as I have this week. I just need to take some more chances that I've given myself on the greens.

"I finished even par on the par-fives this week and even for the tournament and that's not good enough," the two-time major winner added.

"You are looking to play them in 10-under and that would be good enough to win. I will come back next year, try to putt a little better and play the par fives better and you never know."