The 21-year-old American held a four-shot advantage over England’s Justin Rose going into the final round and ultimately won by the same margin after a two-under-par round of 70.

Only Tiger Woods, who finished tied for 17th place on five-under-par, has won the coveted Green Jacket at a younger age, with Spieth five months older than his compatriot was when he claimed his first of four titles in 1997.

Fellow American Phil Mickelson was tied for second with Rose, while Northern Ireland’s Rory McIlroy, who was bidding to complete his major title collection, took fourth place.

Spieth opened the tournament with an incredible round of 64 on Thursday (April 9) and never looked back, carding 66 and 70 in rounds two and three before completing the job today in extremely cool fashion. 

Birdies at holes one and three shrugged off any fears that the youngster would suffer under the pressure, and despite bogeying five and seven, further birdies at eight and 10 steadied the ship once more.

The latter came from an uphill putt, which saw Spieth register a record-breaking 26th birdie of an unforgettable week. 

The Texan's putter let him down at the 12th when he three-putted to drop a shot, but two more birdies at 13 and then 15 took him to 19-under-par, the lowest score ever reached in the tournament’s history.

Despite missing a par putt at the 18th, Spieth happily accepted a bogey to seal the biggest win of his career, with an 18 under total to equal Woods' Masters record.

McIlroy’s best round of the week, a six under 66, saw him finish one shot better off than Japan’s Hideki Matsuyama, who also shot six under.

England’s Paul Casey and Ian Poulter shared sixth place with American Dustin Johnson, who was left to count the cost of a double-bogey five at the par three 16th. 

Woods, who popped a bone in his hand out of its joint when he played a shot from the pine needles on the ninth, slipped down the leaderboard with a sloppy round of 73 and missed out on a place in the top dozen after a bogey at the last.