Could it be his play-off victory in 1975, his success in the Duel in The Sun with Jack Nicklaus in 1977 or even his runner-up finish to Stewart Cink in 2009?

All would be quite reasonable and valid choices, but one performance that would likely make few lists resulted in his largest victory in the Championship.

In 1980, Watson was without a major title since the aforementioned Duel in The Sun at Turnberry. He had claimed three consecutive money-list titles on the PGA Tour in that time, though, and headed to Muirfield for The 109^th Open Championship in fine form. 

A winner of five tournaments already on the PGA Tour that year, and the favourite alongside Jack Nicklaus, the then 30-year-old arrived in East Lothian with a determined look in his eye. An opening round of 68 left Watson tied with Lee Trevino for the first day's lead, before a 70 in round two put him in second place, with only Trevino ahead by three. 

It would be his third-round display that really set Watson apart at Murifield. A sparkling 64, four better than any other player occupying the top-10 at the halfway stage, gave the charismatic American a four-stroke lead heading into the final day's play. 

There would be no doubt who was going to win throughout almost the entirety of round four, as Watson only increased his lead in the early stages. By the close of play, with a 271-stroke total, the Kansas native set his stall out as a modern-day great of The Open with a four-stroke triumph over Trevino. 

At 13 under the card, Watson had been dominant. Behind Trevino came Ben Crenshaw at seven under, followed by Nicklaus and Carl Mason on four under. Nobody else bettered two under for the week.

In fact, the only players who had ever scored lower than 271 at The Open were Watson and Nicklaus, with their respective totals of 268 and 269 in 1977.

Watson would win two of the next three Championships too, taking five of nine from 1975. But astonishingly, his 1980 triumph was the only one of his five total victories where he would win by more than a stroke.

Trevino said after the Championship: "I am not disappointed at coming second to the best player in the world, and it is no secret he is that right now."

While Watson and Nicklaus were a world apart from the field in 1977, the former was on another level all on his own in 1980 at Muirfield. The 109^th Open was far from Watson's most famous victory, but perhaps the case could be made that it was his finest ever performance in golf's original Major.