Yet they all have to go some to bypass Spieth, who led wire-to-wire when winning the Masters aged 22 before, 12 months later, infamously conceding a five-shot lead to Danny Willett. On days like this, when Spieth's willpower lives up to his peerless craft on and around the greens, that capitulation makes absolutely no sense.
There were four bogeys on his card and any number of times when he looked aghast at his caddie, Michael Greller. But he weathered the storm - literally - took refuse under the brolly, dried off his grips and then, when the opportunities presented themselves in a staggering six holes, he unleashed the magic moments.
In this 80-minute spell, he chipped in for a par on the 10th, holed a 35-footer on the 11th, stiffed it on the 12th and made an eagle on the 15th. Indeed, when he made that 20-footer for a three, there was suddenly a three-shot gap and the rest must have gulped.
Yet even Spieth's escapologist powers could enact the rescue on the 16th and he was forced to be content with his one-under heroics.
Once again, he only hit five out of 14 fairways and only eight greens in regulation, but when you are so accomplished with your wedge and only taking 25 putts, it is possible to mask the failings of the long game. But only if the psyche is exceptionally strong.
Spieth dared to call himself "lucky". "I give myself a B grade [for the round]," he said. "I got pretty frustrated through the turn, hitting it into pot bunker after pot bunker and squeaking out pars somehow, but I thought we did a good job after. I played the last eight holes almost as a new round. I didn't get everything I could out of [the first] round and I got more than what I deserved [out of the second]."
With respect to the others looming large, McIlroy's name in close proximity might cause Spieth to sit up and take most notice. The Northern Irishman's mission to stage one of the game's most audacious recoveries is becoming all the more plausible.
Birkdale folklore already has it that McIlroy was five over after six holes in his first round. Since then, he has performed like McIlroy should perform, playing his last 25 holes in six-under, better than anyone over this stretch.
When Kuchar departed the course just before 2pm, he was expecting to return to his rental home to watch joyous mayhem. The 39-year-old was content with his 71 for a four-under total and with the forecast predicting torrential rain and higher winds, he was clearly anticipating retaining top spot. Except it did not quite work out like that.
Yes, there were downpours, coming in sustained bursts of such magnitude they created a 20-minute suspension of play as the greens were cleared of standing water, and the flags did begin to bend in the gusts which, on occasion, hit 55km/h. But while there were some casualties - Justin Thomas, the world No 13 made a quintuple bogey nine on the sixth on the way to an 80 - the pick of the afternoon starters battened down and withstood the elements.
Poulter, who finished second here in 2008, remarkably managed to keep a bogey off his card until the 16th. The 41-year-old then looked almost certain to take another at the 18th, when he played a sloppy six-iron to the left of the green, short-siding himself behind a greenside bunker. But from there, he played a quite marvellous lob-wedge to two feet.
"To be in after two days and be under par for this championship after the way I started, I'm ecstatic," Poulter said after a 68, pointing out that he was eight shots better on the first six holes this time. "I went out with positivity and trust in myself and just need to keep that for the next two days."
Poulter has that look on his face, yet having resurrected his career with his runner-up finish at The Players two months ago, he is also swinging with great freedom.
This is the first major he has played in since the 2016 Masters and having come through the 36-hole shootout at Woburn a fortnight ago, he is determined to enjoy himself. He revealed that on Thursday night his eldest son, Luke, had taken £20 off John
Daly's son, John jnr, in a challenge match and the father, too, is ready to take on all-comers. Be it Spieth or whoever.
"I'm in a bonus week - I qualified," Poulter said. "I'm loving it. I really am. This is a massive bonus for me to be in this position. I haven't played a major for a while and I'm excited, I'm pumped up. I feel my game's coming back to form. So I'm ready to go toe-to-toe with anyone this weekend."
