Some 62 minutes into this match at Semple Stadium, Kevin Moran lofted a delightful ball over the top of the Cork defence, where Eoin McGrath had stolen a metre of vital space.
McGrath had been a surprise introduction for Tomas Ryan 20 minutes earlier and had been struggling to get into the game.
Still, this looked like the moment, his moment. It had goal written all over it once it left Moran's stick. All he needed was composure.
Waterford were leading by 0-18 to 1-13 at the time and a cool take and finish would surely have buried a fragile Cork side that were struggling with their opponents' growing momentum.
But McGrath spilled and the danger was averted. The chance to kill the game was lost.
In the great drama that has encased Cork and Waterford clashes over the last decade, there are always twists and turns, but this was the most critical juncture here.
Within a minute Patrick Horgan had clipped over a point from a free at the other end after Luke O'Farrell was fouled, and then Darren Sweetnam, one of Cork's most influential replacements, switched on the turbo to clear the chasing pack and set up O'Farrell for the levelling score.
In all, Cork would outscore Waterford by 0-6 to 0-1 in those closing 10 minutes after that McGrath chance, with Sean Og O hAilpin's late point, Cork's second last of the afternoon, raising the roof among those in red in the 38,116 crowd.
Waterford could also point to a John Mullane wide from an angle he likes five minutes earlier or the wrong option taken by another substitute Shane Casey not long after. But this was the key moment.
A 12th meeting between these great foes in a little over a decade underlined once again that their rivalry is among the healthiest.
Neither county has to be at their best to produce an enthralling contest.
Jimmy Barry-Murphy was at pains to hail the win but not so much the performance afterwards, intimating how he thought there was much more to come from his Cork side.
But they need some stability to team selection from now on after so many extensive makeovers in the last three months.
Getting to Croke Park for an All-Ireland semi-final was always the treasured target and now that it has been achieved, Cork will feel they are in bonus territory from here.
Barry-Murphy used his bench well. Sweetnam was a much greater running threat than Daniel Kearney and Cathal Naughton gave a timely reminder that he has much to offer with his pace, while the decision to recall O hAilpin was wholly justified, especially with the big last quarter he put in.
But there were moments when they appeared to struggle physically against the likes of Seamus Prendergast, Michael 'Brick' Walsh and Moran.
For Cork to thrive, their forwards must become as adept at winning the ball as they are at using it.
Barry-Murphy was being brutally honest when he suggested afterwards that yesterday's performance wouldn't be good enough to beat Galway.
They had started well against the wind and might have been a goal ahead in the opening seconds when O'Farrell's shot crashed off the underside of the crossbar and somehow stayed out.
But by the 16th minute they had found the net courtesy of a scintillating move that underlined the potential in these young forwards.
Cian McCarthy and Paudie O'Sullivan were involved in the approach work, O'Sullivan's reverse pass sending Jamie Coughlan, a late replacement for virus victim Conor Lehane, into space.
Three Waterford defenders converged on Coughlan but he was able to step outside them and plant a shot past Stephen O'Keeffe for a six-point (1-5 to 0-2) lead on 16 minutes.
But from then until the break it was Waterford who thrived. Tony Browne's free from inside his own half, after Kearney took Mullane high, triggered communal fist-pumping that brought renewal among the Deise players.
Recognising the need to bolster their midfield, they switched Moran on to Pa Cronin, who had been dominant, and moved Mullane out to left half-forward, where his influence was profound, badly discommoding a previously comfortable O hAilpin until Tom Kenny switched over on him.
In that time Mullane won two frees and had an involvement in another three points, and it was his moment of genius that set up Pauric Mahony for his second point on 29 minutes, before he and Moran combined to send in Stephen Molumphy as that early six-point lead was wiped out, albeit with the advantage of the wind.
Maurice Shanahan soon had them in front but Cork still led at the interval, 1-9 to 0-11.
Molumphy's influence grew as the second half wore on and his drive won a free for Shanahan to restore parity at 1-10 to 0-13.
Inevitably, there was controversy over a score. Cork substitute Stephen Moylan's 56th-minute shot looked good but was adjudged to have gone wide by the officials. Waterford kept pressing and probing, and through Moran, Molumphy and Walsh they had a grip in the middle. Up to that McGrath chance they looked the more likely winners.
But the momentum then switched to Cork, and Sweetnam and Naughton were able to make the vital metres to stretch Waterford's tiring legs.
What should Waterford take from the season?
They can't be too despondent, but over the next 12 months they really have to work at expanding their squad and getting the likes of Bryan O'Sullivan, Shane Sullivan and Daragh Fives back will be of paramount importance.
When Deise manager Michael Ryan turned to his bench here he didn't have the same options as Barry-Murphy, and what options he did have he didn't use them well.
Scorers -- Cork: P Horgan 0-7 (4f), J Coughlan 1-1, C McCarthy 0-3, P O'Sullivan, P Cronin, C Naughton 0-2 each, L O'Farrell, S Og O hAilpin 0-1 each. Waterford: M Shanahan 0-9 (6f, 1 '65'), P Mahony 0-3, J Mullane, S Walsh 0-2 each, T Browne (1f), S Prendergast, S Molumphy 0-1 each.
Cork -- A Nash 8; S O'Neill 8, S McDonnell 7, B Murphy 7; T Kenny 7, E Cadogan 6, S Og O hAilpin 8; D Kearney 5, P Cronin 7; N McCarthy 6, C McCarthy 7, J Coughlan 7; P O'Sullivan 7, L O'Farrell 7, P Horgan 7. Subs: D Sweetnam 7 for Kearney, (ht), C Naughton 8 for N McCarthy (46), J Gardiner 6 for Cadogan (50), S Moylan 6 for Coughlan (56), L McLoughlin 7 for C McCarthy (59)
Waterford -- S O'Keeffe 7; N Connors 7, L Lawlor 6, S Daniels 7; T Browne 6, M Walsh 7, K Moran 8; S Molumphy 8, Philip Mahony 6; M Shanahan 7, S Prendergast 7, Pauric Mahony 7; J Mullane 8, S Walsh 7, T Ryan 5. Subs: E McGrath 5 for Ryan, S Casey 5 for S Walsh (59), R Foley for Browne (69).
Ref -- B Kelly (Westmeath)