Masters champion Jordan Spieth has kept the grand slam possibility alive by winning the US Open.

The 21-year-old American fired a final round one-under-69 at Chambers Bay to win by one stroke at five-under 275 from countryman Dustin Johnson (70) and South African Louis Oosthuizen (67).

Playing in the final group, Johnson had a chance to win with a 12-foot eagle putt on the last hole but he three-putted to hand Spieth the title.

Spieth is just the sixth player in history to win the Masters and US Open in the same year, joining Tiger Woods (2002), Jack Nicklaus (1972), Arnold Palmer (1960), Ben Hogan (1951, 1953) and Craig Wood (1941)

He can complete a grand slam if he wins the British Open and US PGA Championship later this year.

Australians Adam Scott (64) and major debutant Cameron Smith (68) were tied fourth at three-under with South Africa’s Branden Grace.

Overnight joint leader Jason Day finished tied ninth after a closing 74 as he continued to battle with vertigo.