For almost four decades, there really was only one answer when it came to the question of The Open’s most iconic head-to-head battle.
The captivating contest between Tom Watson and Jack Nicklaus at Turnberry in 1977 quickly became known as the Duel in the Sun and set the bar for final-round showdowns, the pair streaking clear of their rivals with performances of the highest quality.
Watson himself later argued that his and Nicklaus’ efforts in 1977 had been eclipsed by Stenson and Mickelson’s outstanding performances at Troon.
Our Great Final Days series continues with a look back at the duel of the ‘sons’.
If it seemed like only two people were truly in contention for the Claret Jug as the final day of The 145th Open began, that suspicion was soon confirmed when the leading pair resumed their bids for glory.
Stenson and Mickelson had reached 12- and 11-under respectively through 54 holes, putting them well clear of Bill Haas, who sat third on six-under.
What followed was truly remarkable, with an action-packed opening four holes for the final group setting the tone for an afternoon of high drama.
The lead changed hands immediately, Mickelson punishing his rival’s clumsy bogey on the opening hole with a magnificent approach that set up a tap-in birdie.
Stenson bounced back superbly. After Mickelson had lipped out with a chip for birdie at the second, the Swede walked in a mid-range putt to pull level and then converted from similar distance on the next to reclaim the lead.
Yet there was to be another leaderboard shift on the fourth, where a third birdie in succession for Stenson was bettered by an eagle for Mickelson, leaving both men seven clear of anyone else at 14-under.
After both men birdied the par-5 sixth, Stenson edged in front again at the iconic eighth hole, known as the Postage Stamp. As he had done on the third, Stenson holed a mid-range putt to pile pressure on his opponent and then saw Mickelson miss from a shorter distance.
However, when yet another Stenson birdie putt found the target at the 10th, Mickelson was able to respond with a three of his own to stay just one shot back with eight to play.
Commentating on the Championship, the great Dame Laura Davies said: “It's staggering, really, because you see all these other players, they're missing greens, they're struggling a little bit and these guys keep hitting fairways and greens and chugging along.”
A rare blip by Stenson followed at the 11th as he recorded his second bogey of the day, but Mickelson’s card was kept clean as the American rescued an unlikely par after finding trouble off the tee at the 12th.
"Oh, what a four from Phil Mickelson,” roared Dougie Donnelly. “Every time Henrik Stenson lands a punch, he comes straight back!"
A pair of pars at the 13th left Mickelson and Stenson tied on 16-under, but the latter was about to find another gear.
His birdie from around 20 feet on the 14th was impressive enough, but Stenson then sent the crowd wild by holing a mammoth putt from the edge of the 15th green, moving two clear with three to play.
Stenson kept the pedal down with his ninth birdie of the day on the 16th, though there was a puff of the cheeks from the leader as Mickelson came agonisingly close to an eagle, his ball drifting across the face of the hole.
Such small margins can ultimately decide Championships and Stenson must have known it was his day when his drive on 18 appeared sure to reach the bunker Greg Norman famously drove into in the play-off at Troon in 1989, only to somehow pull up inches short of the sand.
Stenson duly capitalised, firing his approach into the heart of the green to effectively seal victory. After Mickelson had finished with a par, all that remained was to see whether a new scoring record for The Open could be set.
Fittingly, one of the best rounds in Open history was completed with one more outstanding putt, an incredible 10th birdie of the day and fourth in five holes giving Stenson a 63 and a record aggregate of 20-under.
Mickelson’s bogey-free 65 left him on 17-under, 11 shots clear of the third-placed JB Holmes.
On almost any other day, that would have been enough to secure the Claret Jug. Yet having been to second at Mickelson at Muirfield three years earlier, it was now Stenson’s turn to be crowned as the Champion Golfer of the Year.