On Tuesday, it was all going horribly wrong. At two o’clock, Great Britain’s world number one-ranked slalom canoeist David Florence paddled across the finishing line of the Lee Valley white water course and slumped over his splash deck – his time not even good enough to make the final.
Another favourite, another failure, another image of anguished disappointment to add to the back-page blow-ups that had already featured the famous faces of Cavendish, Adlington and Daley lost in silent recrimination.
The most arresting sight of all, of course, was the medal table. Great Britain sat behind Lithuania and Georgia; rivals like France and Korea had already established commanding leads. No-one was writing the Games off, but when every day brought countless reminders of the high price of a slow start, it seemed that critical momentum had been squandered.
And the thought, too horrifying to articulate, crossed our minds that home advantage might not be an advantage at all, but an insurmountable monolith of now-or-never pressure and expectation.
Yes, on Tuesday, it was all going horribly wrong.
So how on earth was it that on Saturday, we were incredulously acclaiming a gold rush of joyously relentless contagion, a runaway train of success that hurtled from rowing lake to velodrome to athletics stadium in a blur of cheers, tears and Union Jacks?
Six golds, each one a masterpiece (the word used by the eloquent Andy Triggs-Hodge to describe the performance of the men’s four), and most importantly, a giant Greg Rutherford-esque leap up the medal table to third.
The individual merits of each performance should not be overlooked, from the meteoric rise of rowing ingénues Kat Copeland and Sophie Hosking to the brave indefatigability of the aforementioned long jumper, who had overcome 17 hamstring tears.
But it was as a bravura shock-and-awe display of collective might that Super Saturday was most impressive: and underpinning it all was the characteristic virtue of delivery under pressure.
As cycling supremo David Brailsford has suggested, there is no magic to Team GB’s glittering successes, not even on days like Saturday. They are the result of a philosophy of rigour that relishes every aspect of performance, no matter how humdrum or nebulous, as an opportunity for improvement. Pressure is just another variable to be recognised, demystified and mastered.
The director of elite performance is Clive Woodward, a man who prepared his all-conquering rugby teams for battle by inscribing on the changing-room wall the initials TCUP: think clearly under pressure.
The imprint of that mantra has been visible in numerous British performances.
19-year-old Philip Hindes slid off his bike on his first Olympic ride, but in the final minutes later produced a 17.2-second first lap, his finest ever start, to propel the team sprinters to glory.
The showjumping team, under the almost unimaginably excruciating pressure of a jump-off, conjured a clear team round, a better performance than they or any other team had managed during the competition proper.
And what about Super Saturday’s Jessica Ennis, a paragon of serene excellence in the face of overwhelming public expectation. British athletes have seemingly decrypted sport’s kryptonite.
Look again at Team GB’s assured turnaround from a stuttering start to Saturday’s dazzling climax and we see simply the macroscopic version of the model each individual athlete has been drilled in for years: when the pressure increases, so too does the performance level.
For a nation used to watching its footballers wilt in high-intensity situations, these are truly days to savour. As we celebrate the abundance of precious metal hung around our Olympians’ necks, we should reflect that their mettle is more precious still.
