Rank outsider Louis Oosthuizen was closing in on British Open glory on Sunday as he calmly defended a four-stroke overnight advantage down the front nine of the final round.
The 27-year-old South African carded superb rounds of 65, 67 and 69 to set up a 15-under par winning position and only England's Paul Casey with rounds of 69, 69 and 67 managed to hang onto his coattails.
The rest of the field was led by Martin Kaymer, and even the German said he did not expect to close the gap on the leader from seven strokes back, conceding that it might well be a two-horse race.
Casey had an immediate chance to crank up the pressure on his more inexperienced playing partner when he hit his approach to witnin five feet at the first, but he pushed his putt wide.
The Englishman then bogeyed the second to provide Oosthuizen with the perfect start as he himself held firm with two pars to stretch his lead to five.
Casey had another chance to pull one back at the par-five fifth but again failed to sink a makeable birdie putt.
Ahead of them, no-one among the chasing pack was able to mount a charge.
Kaymer, who had been in third overnight at eight over, bogeyed the first, while Henrik Stenson of Sweden, Lee Westwood of England and Alejandro Canizares of Spain all parred the first four holes when it was birdies they needed to stand a chance of reeling in the leader.
Oosthuizen, whose only tour title came at the Andalucia Open in March and who was ranked 54th in the world, would be the fourth South African to win the Open after Bobby Locke (1949, 1950, 1952, 1957), Gary Player (1954, 1968, 1974) and Ernie Els.
Near-perfect playing conditions marked the final day and the forecast was for bright and breezy conditions for the rest of the afternoon with gusts of wind up to 30 mph.
World number one Tiger Woods, whose hopes of an unprecedented hat-trick of Open wins at St Andrews all but evaporated with a disappointing 73 on Saturday leaving him 12 shots off the lead, birdied the first and third holes.
But a double-bogey six at the fourth where he needed two shots to get out of a bunker put an end to any hopes he harboured of mounting a last-day miracle charge.
The fallen superstar then endured another double-bogey four at the seventh as he sunk to just one under par for the tournament. Woods hit back with birdies at the ninth and 12th.
The pressure on Oosthuizen was intense as he bid to become the biggest upset winner of the Open at St Andrews since American Tony Lema won on his debut in 1964.
And 32-year-old Casey, too, has an eye on history as he bids to end years of under-achievement by him at the majors and in so doing become the first Englishman to win a major title since boyhood hero Nick Faldo at the 1996 Masters.
Faldo was also the last Englishman to win the Open, in 1990, also at St Andrews.
As for the rest of the field, they were left hoping that either Oosthuizen would buckle under the pressure of the moment, or they would be able to shoot in the low 60s, as did Greg Norman with a 64 to win at Royal St George's in 1993.