The agony was palpable as Wiaan Mulder and Temba Bavuma ground their way through a third-wicket stand of six that spanned 40 interminably accurate balls.
Hard length on off stump... nip, bounce, rinse, repeat. Some balls were stared down, and patted straight back whence they came. Others seared past the splice, to the oohs of a stacked cordon and the groans of a packed South Africa contingent in the stands, whose previous sense of a day well dominated was retreating with every non-shot.
Despite facing 132 balls in a fraught evening session, close to 50% of South Africa's 43 runs came from exactly five scoring shots - a trio of driven boundaries from Ryan Rickelton at the top of the order, then two more fours in consecutive deliveries at the absolute close of play, as Pat Cummins over-reached in his bid for an inswinging yorker, and gifted David Bedingham a brace of leg-stump freebies.
Yes, there was a certain dignity in South Africa's strokeless defiance, most particularly from the captain Bavuma, who will resume on 3 not out from 37 balls on Thursday morning with another vast burden to shoulder. And yet, in between whiles, there were four very emphatic wickets - three of them bowled, and the fourth snicked to first slip - as Australia's magnificent seam attack, all 955 Test wickets between them before the start of the WTC final, accepted the invitation to come at their opponents and bowl their best balls without any real threat of retaliation.
"I thought the guys bowled pretty well, to be fair," Steven Smith said at the close. "It wasn't the easiest surface to come out and wallop it. The couple of times they went at it and tried to drive the ball, we got the edges. A couple [of them] played nicely when they were late and defending under their eyes. They were difficult to get out. It's the kind of wicket you've got to be solid in defence and, when you get a loose ball, you pounce on it."
Smith's logic was sound enough, and earlier in the day, it had been borne out in his own performance - a vital 66 from 112 balls that was as composed in its compilation as Beau Webster's 72 had been neurotic: "for his first 30 balls, it didn't look like he could spell 'bat'," as Smith evocatively put it at the close. As Kagiso Rabada proved with his own magnificent five-for, this pitch has plenty to offer to the very best in the business.
Even so, it was an atypical day of Test cricket for the many neutrals in the stands - in other words, the regular Lord's clientele who have got used to watching England take a radically different approach to batting in recent seasons. And there were doubtless some conflicting emotions at play as a consequence.
On the one hand, it's fair to assume that most of those neutrals would have been urging South Africa to start giving it some welly (because, let's face it, everyone loves an underdog in these parts, especially when they aren't Australian). But also, for those with memories that stretch back longer than three years, there might also have been a ghastly realisation: yikes, this was us once.
Whether or not Bazball is an actual thing that Australians acknowledge as a tactic, Cummins' team saw the whites of its eyes on this ground two years ago. In the 2023 Ashes, England served up perhaps the diametrically opposite performance to today's fare, particularly, in a first innings of such self-immolating recklessness that they wrecked their own chances of victory by swinging too high, too hard, and too often. Alex Carey's instincts in the second innings may have ignited a furious final act, but the match - and the Ashes - were lost in that blizzard of over-eager aggression.
Even so, the manner of that defeat was infinitely preferable to - and, in fact, a direct consequence of - the experience England had endured in their previous encounter with the Australians in 2021-22: a trial by paralysis, of precisely the type that South Africa experienced today.
The nadir of that series was reached in the third Test in Melbourne - a strokeless surrender in which Haseeb Hameed, not unlike Mulder today, batted to the absolute limit of his brief in making seven runs from 41 balls across two innings, as Scott Boland served up the ridiculous second-innings figures of 6 for 7.
And if England, in that moment, declared "never again", and vowed to find a different way to shape their narrative, then it needs also to be acknowledged that they did so from a position of privilege: as a Big Three nation, with the financial clout to schedule 22 Tests in a WTC cycle, compared to South Africa's 12, and with the certainty of selection that allows their players to chase their shots with impunity. Zak Crawley's entire Test career has been built on the premise that one false move will not bring down either his ambitions, or those of the men around them.
It's not so simple for South Africa at this delicate juncture of their evolution. Win this Test, and the team's development might yet be self-perpetuating - amid the interest and accolades that come from being world champions. Lose, however, and maybe it'll be back to the square minus-one that they faced at the start of this cycle, when Neil Brand (remember him?) led a scratch first-class squad to get crushed in two Tests in New Zealand, while the main characters got stuck into the first season of the SA20.
So, it's hard to argue that South Africa played their cards wrong today. "One does not simply walk into Mordor and Bazball," as that Boromir meme might have put it, not even when you've recruited one of the concept's chief architects, Stuart Broad, to impart some mindset gems.
But what's a team to do when faced with one of the very best attacks in Test history, on a pitch which, as Smith put it, was "doing enough all day... [with] a bit of variable bounce and a bit of sideways movement"?
More of the same, presumably, when Bavuma and Bedingham resume on the second morning, with brighter sunshine in prospect, but with a dry surface already itching to bring the spinners into play - if and when they are required. For Smith didn't anticipate any significant deterioration in the ball's hardness until the 40th over, which was when Webster's first-innings effort had been able to escape the pressure and develop into something meaningful.
But for that to transpire in the current conditions, South Africa's remaining batters will need to endure for the best part of the morning session without further error - and even then, as Carey showed with the ill-conceived reverse-sweep after tea that triggered Australia's dramatic loss of five wickets for 20 runs, you're as likely to be damned for doing as you would be for sticking to your original plan.
At moments such as these, though, you're still entitled to wonder whether it's more reckless to roll the dice, or to dig in with such blinkered determination that you're closing yourself off to the inevitable.