It was not so much the duel in the sun as the grind in the gloom, but what a grind, what a colossal tussle between our new leader in the 145th Open championship, Henrik Stenson, and the man who will be seeing the dogged Swede in his sleep, Phil Mickelson.
One shot divides them after a fiercely competitive third round that swung this way and that. Mickelson walked to the first tee with a one-shot lead, which he lost after one hole, then he fell behind after four, drew level after six and regained his lead after eight.
He was ahead by two shots after 13 holes and then lost them both on the 14th. Mickelson regained the lead on 16 only to lose it again, in another dramatic two-shot swing on 17 when Stenson sickened him with a rare birdie on the brutal par three.
Mickelson made four and that's the way they finished; 12 under to 11 under. They'll do it again on Sunday, an epic joust to the end.
Intense and captivating
"I've got two thirds and a second and I'm not looking to pick up anymore of those finishes," said Stenson, who was runner up at Muirfield in 2013 and third at St Andrews in 2010 and Royal Birkdale in 2008.
"There's only one thing that matters. I know Phil is not going to back down and I'm certainly going to try to not back down as well."
In the Swede, Mickelson found an opponent who steadfastly refused to go away. The American conceded he was "a bit off" in his game.
"I didn't have my best stuff," he said. "I was a little bit jumpy and my rhythm wasn't very good. It could have been a day that got away from me, so I'm proud of that."
True, the golf wasn't as electrifying as the 1977 vintage of Jack Nicklaus and Tom Watson up the coast at Turnberry in the original 'duel in the sun', but it was intense and it was captivating.
Stenson shot 68 to Mickelson's 70. Nobody else counts. Bill Haas is the nearest rival and he's six shots adrift of Stenson and five behind his fellow American. The leaders are so far ahead they can't even see traffic in their rear-view mirror.
They walked to the first tee at 15:15 BST, Mickelson first and Stenson behind. "Go on Stenson, lad," came a shout from the top of the stand overlooking the tee, quickly followed by a retaliatory holler of "Go, Phil."
Mickelson acknowledged his fans, Stenson just stared straight ahead. The Swede birdied the first and the third and all of a sudden we had co-leaders at Royal Troon.
Second at Muirfield - to Mickelson - three years ago and there Stenson was alongside the American again.
And there Mickelson was reloading on the fourth tee after blasting "way right!" on the long par five. He recovered for par; Stenson made birdie. The Swede led by one. Out there on the course there was a sense of a real duel about to take place.
Both of them walked from the fourth green to the fifth tee and they bumped fists with young fans along the way. They were already five and six shots clear of the field. Nobody else mattered bar these two. There was nowhere else you wanted to be than right there watching them.
It was strange, though. The crowds thinned and the noise died away. The golf flitted from scrambling to magisterial but there was rarely a special occasion atmosphere about it until they bore down on those closing holes and came into view of the big grandstands.
It might not have had the backdrop of thunder for much of the day, but this was fervent golf from two golfing warriors. It was terrific.
A psychological battle
On the sixth, Mickelson hit his tee shot left and his second shot left again. He stared in wonder at that second blow, a kind of scooped slice that ended up by a TV tower. "Love you, Phil," came a cry from behind the ropes as Mickelson looked into the distance. He smiled, touched the peak of his cap and walked on.
He saved his par, but Stenson couldn't. And so continued a terrific ebb and flow, a tense day that demanded nerve and mental courage as much as ball-striking. There was a psychological battle going on between them, a Ryder Cup feel to their head-to-head.
Stenson found trouble at the Postage Stamp eighth, played a bunker shot with one leg in and one leg out of the sand and failed to make par. Mickelson led by one again. Then he led by two when making birdie on 13, then he didn't lead by any after bogeying 14 to Stenson's birdie.
Earlier in the round, after Mickelson had pulled off a wondrous up and down beside the third green off a tight lie, over a bunker to a tiny target, the two men chatted about wedges on their way to the next tee.
Now there was no chat, just golfing poker. There was a swing on 16 when Mickelson birdied to hit the front again on 12 under, then a bigger swing on 17 when Mickelson bogeyed and Stenson birdied. The Swede led once more - and this time he kept it.
What would it mean to him to win? "Massive," he said. "This is the one thing I'm looking for. I give myself 50-50. It might happen, it might not happen. The sun will come up on Monday anyway. Maybe not in Scotland, but in other parts of the world..."
He smiled and left and on Sunday he might become a Major champion. It would be overdue and deserved, but what an enormous challenge lies ahead of him - with an Open champion now in pursuit.