Conor Hazard was the Celtic hero as the Hoops rewrote the history books yet again with a dramatic 4-3 Scottish Cup final penalty shoot-out win over Hearts following a 3-3 draw after extra-time at Hampden Park.
Neil Lennon's side seemed to be cruising at half-time after Ryan Christie's stunning opener after 19 minutes preceded Odsonne Edouard's 'Panenka' penalty 10 minutes later.
However, Jambos striker Liam Boyce reduced the deficit three minutes after the break and defender Stephen Kingsley levelled in the 66th minute, both with headers, to make it 2-2 before extra-time.
Leigh Griffiths – who had replaced Edouard after 96 minutes – put Celtic ahead before fellow substitute Josh Ginnelly levelled for the Jambos.
Then came the chance for the 22-year-old Northern Ireland goalkeeper to shine in only his third game for Celtic.
Griffiths and Callum McGregor scored from the spot before Jambos stopper Craig Gordon saved from Christie.
Steven Naismith, Michael Smith and Olly Lee netted their penalties before Hazard saved from Kingsley and Craig Wighton and – with Mikey Johnston scoring – Kristoffer Ajer hammered home the winning penalty to seal an unprecedented quadruple domestic treble.
It was also a record fourth-successive Scottish Cup win with the club's 12th-successive trophy in the delayed final from last season.
Lennon had tinkered with his side with veteran skipper Scott Brown replacing Ismaila Soro and Christie in for Jeremie Frimpong, while Hearts brought back midfielder Andy Halliday for Olly Lee.
The Tynecastle side started brightly and Hazard made an early save when Christophe Berra helped on a free-kick by Andy Irving.
Hazard then misjudged a through ball by Michael Smith and was relieved to see Naismith's sliding toe-poked effort from outside the box roll wide.
Christie was far more accurate and with greater effect when he picked up a loose ball from Aidan White's header and curled the ball high past Gordon and into the net.
Celtic's second came after referee John Beaton pointed to the spot when Shane Duffy's header from a David Turnbull corner struck Berra's outstretched arm.
Edouard calmly strolled up and chipped the ball into the net as Gordon dived to his right with the former Celtic keeper booked for throwing the ball at the celebrating French striker in apparent anger.
The match was in danger of slipping out of the Gorgie side's reach.
Gordon then saved a shot from Edouard with his feet as Celtic threatened again and at the interval there looked to be no way back for the Edinburgh side.
However, with the second half barely started, Boyce's close-range header from a Halliday cross gave the men in maroon some hope which was soon almost quashed.
Moments later, only a great save from Gordon prevented Edouard converting a Greg Taylor cut-back.
Ginnelly replaced Jamie Walker in the 57th minute and was presented with a chance moments later when Duffy and Christopher Jullien bumped into each other leaving the substitute an opportunity to shoot but Hazard parried and the danger was cleared.
Hearts dramatically levelled when Kingsley raced in at the back post to head in from Ginnelly' corner – goal-line technology telling referee Beaton the ball had crossed the line before it was cleared, after play was originally allowed to go on.
Rain continued to cascade as tension increased.
Edouard missed the target from a Taylor cross and Ginnelly flashed a shot high over the crossbar in the first of five added minutes which came before extra-time.
Berra and substitute Wighton fired over for Hearts before Griffiths made his mark.
After Brown's header from a Christie corner was blocked by Gordon, the former Hibernian player was on hand to knock the ball in.
But back came Hearts and in the 110th minute, after Hazard failed to deal with a searching free-kick from Lee, another substitute, Kingsley headed the ball across goal and Ginnelly forced it into the net, setting up the drama of penalties and with it more Celtic history.