Such is the subjective nature golf that it would be almost impossible to decide upon a concrete winner it the category of 'greatest upset in a major.'
Jack Nicklaus' masterclass at the 1986 Masters - where he became the second oldest winner of a major championship - would certainly be a contender, along with Shaun Micheel's triumph at the 2003 PGA Championship and Jack Fleck's against-all-odds victory at the 1955 Open Championship.
In my mind, Y.E. Yang's performance at the 2009 PGA Championship at Hazeltine - where he duelled Woods and came out on top - is right up there.
Entering the tournament, the little-known Korean was ranked 110th in the Official World Golf Ranking. He opened with rounds of 70 and 73 to make the cut in a tie for 9th on one-under-par, before a Saturday 67 propelled him into a tie for second place, two behind Woods.
Before the final round, no one gave the Korean much of a chance, and rightly so. He was, after all, playing in the final group with the world number one, a man who, on 14 previous occasions, had never been overturned when entering the final round of a major with the lead or a share of the lead.
What's more, it was the first time he had ever played alongside Woods, and he had the added pressure of knowing victory, no matter how unlikely, would make him the first Asian to win a major championship.
He started the day two behind, but cut the deficit early on with a birdie at the third hole. He gave one back at the fifth and parred out for a level-par front nine, but it was enough to catch Woods, who went out in two-over par.
Both players started the back nine on six-under-par. Woods moved ahead with birdie at 11 but gave it straight back on the next hole.
Standing on the 14th tee - a drivable par 4 - the pair were still level, and locked in a titanic battle. It was here Yang stood up to be counted. His tee shot finished short of the green and, whilst his chip up the putting surface wasn't a difficult one, no one expected him to hole it. To his credit, Woods made a three, but sat one behind with four to play.
Both players parred 15 and 16, and both dropped shots on the difficult par 3 17th.
The tournament was still wide open, with only one shot separating the players. Surely the pressure would tell on Yang, and Woods would claim his 15th major title? Wrong.
Both players found the 18th fairway, but Yang still had 217 yards to go, semi-blind over trees, to a green surrounded by heavy rough.
What followed will go down as one of the greatest shots in major championship history, and I must echo the sentiments of Sky Sports' Rob Lee, who proclaimed afterwards: "that's the best shot I've ever seen."
Yang hit the best hybrid of his life, carrying the trees and landing his ball inches away from the cup, setting up a ten-foot birdie putt. Woods, still reeling, missed the green with his approach and, after he failed to chip in, Yang casually rolled in his putt to cap off one of the most reamarkable days in the history of major championship competition.
