Cathal Heneghan was the super substitute as NUI Galway braved atrocious conditions to clinch their first Electric Ireland Sigerson Cup title since 2003.
Level at half-time amid driving rain at IT Carlow's grounds, NUI Galway reeled off six points in a row to put themselves in a winning position - with Heneghan scoring three of them.
The Roscommon senior only came on at the interval but ended up walking away with the Man of the Match award.
Gavin Burke, Paul Kelly and Mayo attacker Fionn McDonagh all capped strong performances with important scores too.
The landmark win, NUI Galway's 23rd, keeps the university on course for a potential third level double with their Fitzgibbon Cup side already through to Saturday's decider.
UL talisman David Clifford did his best to prevent the defeat with 1-2 overall, bringing his tournament takings to 6-22.
His 45th minute penalty conversion inspired a comeback that took the Munster side to within a point.
They would be a point back again with just four minutes remaining when fellow Kerry man and former Kingdom minor star Paul Walsh pointed.
But that was as good as it got for them with late NUI Galway points from Burke, McDonagh and Galway star Tomo Culhane sealing a memorable win.
NUI Galway, slight underdogs, played with the wind initially and wondered if they'd kick themselves for not making more of that initial advantage as they butchered a number of decent chances.
They did surge three points clear early on thanks to scores from McDonagh, Kelly and Burke but didn't score again until early in the second as UL reeled them in to leave it 0-3 apiece at half-time.
Amid driving raing and high winds, two Clifford points from frees helped haul UL back after that slow start to level the game at the break.
But it was a difficult watch as both sets of players struggled with the rain sodden conditions.
Kerry All-Star Clifford attempted to light up proceedings with an audacious lob when he spotted the 'keeper off his line in the 26th minute but the shot held up in the high wind and was off target anyhow.
Heneghan's introduction was the game's turning point and he reeled off the first two points of the second-half before Matthew Tierney clipped over a free for NUI Galway
NUI Galway struck six unanswered points in total and while UL battled back bravely with Clifford converting the penalty, their bid for a maiden title came up short.
NUI Galway: C Carroll; E Kelly, N Mulcahy, C Murray; R Egan, S Kelly, G Durcan; P Kelly (0-1), M Tierney (0-1, 1f); F McDonagh (0-2), N Mullen, C Donoghue; G Burke (0-2), C Sweeney, T Culhane (0-3, 2f)
Subs: C Heneghan (0-3) for Donoghue h/t, T Gill for Durcan 42, R Monaghan for Mullen 64.
UL: C Flaherty; C Donnelly, J Coyne, P Maher; G O'Donovan, S Powter, E McLaughlin (0-1); C Dempsey, D Walsh; C Downes, E McMahon, D Gray; P Towey (0-1), D Clifford (1-2, 1-0pen, 0-2f), D O'Sullivan (0-1).
Subs: J Glynn for Powter h/t, P Walsh (0-1) for Dempsey 42, O Looney for Downes 55, J McCarthy for Gray 58.
Ref: D Gough (Meath).
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