Two first-time visitors to Australia, with a solitary half-century from ten previous Tests between them, their reputations were so lowly that they could only get better, or so the selectors' logic would have you believe.
But lo and behold, by the close of another frenetic, absorbing first day at the Gabba, Vince had replaced that blanked-out question mark on his profile page with a perfect array of no-filter cover-drives, while Stoneman - in reaching his fifth consecutive half-century of the tour - had announced himself as the sort of imperturbable left-handed nugget upon whom English Ashes victories Down Under have recently been founded.
But before anyone starts to equate Vince's elegance with Michael Vaughan's tour de force in 2002-03, or Stoneman's insouciance with Chris Broad's and Alastair Cook's efforts in 1986-87 and 2010-11 respectively, it's worth taking a second look at a scorecard that confirms how hard England were forced to battle for even a share of the spoils.
Despite enjoying periods of rare dominance in the midst of a second-wicket stand of 125 that, remarkably, outshone any England partnership at any stage of their dismal last visit in 2013-14, England started and finished the day in a rare old scrap - first with Mitchell Starc exploiting once again Cook's weakness against quality left-arm seam to bag him for 2 in the third over, and then in the twilight, as Nathan Lyon in particular backed up his extreme pre-match lippiness with one of the finest wicketless spells of first-day offspin ever witnessed in an Ashes contest.
Lyon did, however, produce the single most significant moment of Australia's day - a pinpoint pick-up-and-shy from the covers to run out Vince for a career-best 83. It was the opening that his side desperately needed, and while it may not have been fully exploited before the close, the loss of Joe Root, lbw to the persevering Pat Cummins for 15, did leave Moeen Ali and Dawid Malan clinging on to the close. They did so in a gutsy 33-run stand, but when play was controversially suspended moments after a tight lbw appeal from Starc against Malan, the day's honours had been left more or less even at 196 for 4, even if Australia's second new ball was a mere three deliveries old.
How much of a difference would it have made to the balance of power had Vince made it through to the close? It's not the sort of rhetorical question that had been predicted when he was recalled - amid scenes of barely surpressed mockery - to be England's nailed-on Ashes No. 3. After all, his Test career had appeared dead in the water when he was dropped after the 2016 home summer, with 212 runs at 19.27 to his name.
But the selectors evidently saw something in the quality of his shot-making that deserved a second chance, and in powering past his previous Test best of 42, he returned that faith in spades.
Under overcast skies and with palpable humidity in the air, there must have been a temptation for England's captain, Root, to bowl first after winning the toss - not that such a course of action is remotely acceptable in Ashes contests these days, given what happened when Nasser Hussain went down that route in 2002-03.
Instead, Root trusted in his untested top order to deliver the goods, and from the moment the shine went off the new ball and the sluggish nature of Kevin Mitchell Jnr's final Test wicket was fully revealed, any lingering doubts about his wisdom had been vanquished. Not that he really wanted Vince to be involved in the action as early as the third over - but, having avoided temptation in Mitchell Starc's first over, Cook had no riposte to a perfect off-stump outswinger that kissed the edge through to Peter Handscomb at first slip.
But right from the outset, Vince had his game brain in full working order. With Australia's three seamers favouring a full-length approach, there was ample opportunity for Vince to unfurl his favourite cover drive, and one stroke in particular - off Josh Hazlewood in the 11th over - was pure Vaughan in poise and execution. He had one significant let-off on 68, when Tim Paine, of all people, shelled a snick behind the stumps off Lyon to leave the wicketkeeper's card marked seven years after his last Test. Fortunately, Lyon himself made sure that the damage wasn't irreparable.
At the other end, Stoneman showed that Cook's influence persists even when his form isn't quite as it might be. His judgement outside off was impeccable, particularly against the probing Starc, as the pair's partnership was stretched across 52 overs plus a lengthy rain delay that pushed the tea interval back by an hour and 20 minutes, and effectively forced them to make two separate starts to their innings.
At the culmination of a month of ceaseless Ashes hype, crowned with a week of the purest trash-talk in Brisbane, the manner in which they drew the sting of the most feared Australian venue of them all was inspiring, and at times distantly reminiscent of England's famous second innings on this ground in 2010-11.
But, having nudged coolly along to a Test-best second half-century, it took the ball of the day from the energetic Cummins, a reverse-swinging howitzer that trimmed the top of his bails, to send Stoneman on his way in the closing moments of the afternoon session.
It was a telling breakthrough, with Australia just beginning to make the old ball talk, and though that ball did have to be changed after landing in a puddle by the boundary's edge, Cummins soon found the length and the skill with the replacement to thud a big inswinger into Root's pad to pin him lbw for 15.
At 163 for 4, England were a couple of quick blows from squandering their hard-fought position, and with Lyon settling into a edge-threatening rhythm against the left-handed pairing of Moeen and Malan, the prospect of the Gabba making a Kraken-like awakening could not be remotely ruled out.
Both men lived dangerously, beaten time and again outside off, as the floodlights blinked into action to add a further layer of threat to England's position. But it was Starc's trio of deliveries with the second new ball that offered the starkest reminder of the threat that persists in Australia's ranks. Despite being made to toil, they stayed very emphatically in the hunt. AGENCIES