Cillian Buckley, once an All-Ireland winning colleague of Henry Shefflin's, drove a stake through his old pal's heart with a remarkable additional time goal to keep the Leinster SHC title in Kilkenny.
In a quite remarkable provincial decider, Kilkenny let slip an eight-point 50th minute lead to trail by two with the allotted five minutes of stoppage time up almost up.
It amounted to a 10-point swing on the scoreboard and left Galway manager Shefflin on the cusp of his biggest achievement since taking charge of the Tribesmen.
But with only seconds left in the contest - played out in front of a poor 24,483 attendance - a panicked kicked clearance by Galway defender Padraic Mannion sent the sliotar straight to an unmarked Buckley who returned the ball with interest to the net.
The incredible ending and one-point win means Kilkenny are four-in-a-row Leinster champions and advance through to a 9 July All-Ireland semi-final.
Galway, meanwhile, are still in the race for the MacCarthy Cup and will play the winners of Offaly or Tipperary in an All-Ireland quarter-final on 24 June.
Whether Galway can lift themselves up from this punishing defeat remains to be seen but they at least had the Player of the Match in Conor Whelan who struck 1-06.
TJ Reid finished on 0-09 for Kilkenny while Martin Keoghan, Walter Walsh and defender Mikey Butler grabbed the other goals for Derek Lyng's Cats.
Both sides were much changed from their final round-robin outings with Lyng making four changes to the Kilkenny team that lost to Wexford.
Conor Fogarty and Cian Kenny were both late additions to the team and lined out at midfield while Paddy Deegan wore number nine but came in at centre-back with Billy Ryan also back in attack.
Shefflin welcomed back the injury plagued Cathal Mannion to Galway's midfield and, thankfully for the Tribesmen, his hamstring appeared to hold up.
Jack Grealish was back in defence while Brian Concannon came into the attack.
Concannon was among the early scorers as Galway got off to a jet-heeled start, streaking five points clear as they opened up a 0-06 to 0-01 lead.
It could have rocked another team but Kilkenny impressively wiped out the entire deficit in the space of two minutes to draw level at 1-03 to 0-06 in the 10th minute.
Keoghan's goal was well taken as he was put through close to goal and used all four of his steps to find just enough space to get a shot away that beat Eanna Murphy.
Kilkenny carried all the momentum now and by the 17th minute had turned a sticky situation into an impressive 1-06 to 0-06 lead.
A number of intriguing personal battles broke out around the field; Padraic Mannion on Eoin Cody, Darren Morrissey on Billy Ryan and Gearoid McInerney on TJ Reid at one end and Deegan on Evan Niland, Huw Lawlor on Cooney and Tommy Walsh on Concannon at the other.
Keoghan, who came into the game as an injury doubt, was replaced after 18 minutes but Walter Walsh came on for him and netted within seven minutes, a terrific solo goal after a high fetch above Fintan Burke on the right wing.
Despite that, it was Galway that finished the first half the strongest, reeling off 1-06 in the second quarter of the game to tie it up at 1-12 to 2-09 at the break.
Whelan snatched the Galway goal, when he punished Tommy Walsh and Deegan for not clearing up a breaking ball, and closed out the half with 1-02.
Galway briefly led in the third quarter when Cathal Mannion pointed shortly after the restart but the period belonged to resurgent Kilkenny.
They cut Galway asunder and surged 3-17 to 1-15 clear by the 50th minute, suggesting that the silverware was likely to remain on Noreside.
Butler streaked through for Kilkenny's third goal in the 40th minute after being put clear by Blanchfield following a brilliant catch.
Cian Kenny and Cody were on the mark with scores as well and Kilkenny looked to be cruising towards a 75th title.
From there, however, Galway whipped up a storm, substitute Jason Flynn's 51st-minute goal giving them hope. Whelan came into his own in the final 20 minutes or so, as did Kevin Cooney and between them they registered 0-04 in this period while free-taker Evan Niland, who finished with 0-12 overall, continued to punish any Kilkenny indiscipline.
As the clock ticked over into stoppage time, a three in-a-row of Galway points from Cooney, Niland and Brian Concannon left them two points ahead and apparently on the brink of a landmark win. But there was still one last act in a thrilling drama with Buckley taking centre stage.
Kilkenny: Eoin Murphy; Mikey Butler (1-00), Huw Lawlor, Tommy Walsh; David Blanchfield (0-01), Paddy Deegan, Darragh Corcoran; Conor Fogarty, Cian Kenny (0-02); Tom Phelan, John Donnelly (0-02), TJ Reid (0-09, 0-06fs); Billy Ryan, Eoin Cody (0-03), Martin Keoghan (1-00).
Subs: Walsh Walsh (1-02) for Keoghan (18), Padraig Walsh (0-01) for Fogarty (52), Cillian Buckley (1-00) for Corcoran (58), Timmy Clifford for Phelan (61), Billy Drennan (0-01) for Ryan (68).
Galway: Eanna Murphy; Jack Grealish, Padraic Mannion, Darren Morrissey; Gearoid McInerney, Daithi Burke, Fintan Burke; Cathal Mannion (0-01), Joseph Cooney (0-01); Tom Monaghan, Evan Niland (0-12, 0-08fs), Conor Whelan (1-06); Brian Concannon (0-03), Conor Cooney, Kevin Cooney (0-03).
Subs: Jason Flynn (1-00) for Monaghan (47), Sean Linnane for C Cooney (60), TJ Brennan for Morrissey (64).
Referee: Sean Stack (Dublin).
