When these two sides last met at this stage of the world’s oldest football competition, Don Revie, then-manager of Leeds United, warned supporters against invading the pitch in the event of an upset lest “a player worth a quarter of a million” be injured. He needn’t have worried. His side won 6-0.

47 years later, however, when Sutton’s master of ceremonies spent the final minutes of what will be remembered as one of his club’s greatest victories asking Gander Green Lane to do the same and stay in the stands, he stood no chance.

Sutton’s remarkable journey through this competition continues at the expense of Garry Monk’s Leeds, Championship high-flyers and their biggest scalp yet. A second-half penalty from their captain, Jamie Collins, ultimately proved to be enough for the 16th-placed side in the National League to reach the last-16 of the FA Cup.

You sensed this upset was coming. Monk rang the changes for this game, making 10 in total, not one of them over 25-years-old. Only Stuart Dallas was retained from the midweek win over Nottingham Forest, while Billy Whitehouse and Paul McKay were handed debuts. Malik Wilks was named among the substitutes despite the death of his 19-year-old brother in Harehills on Thursday.

All the early running came from the hosts, who took advantage of their visitors’ evident lack of cohesion. Roarie Deacon, a thorn in Leeds’ side from the first whistle to the last, thought he had opened the scoring early on when he fired decisively into the roof of Marco Silvestri’s net. It was only once the pile of amber and chocolate shirts on top of him had cleared that he noticed the linesman’s raised flag. Offside, just.

The decision only galvanised Deacon. A few minutes later he found enough space again, around 30 yards out, and sent a fizzing, dipping strike at goal. Silvestri was equal to it this time, and impressively tipped over the bar. Sutton could smell blood, and a disjointed Leeds struggled to find a response to the non-League side’s tenacious midfield.

Silvestri was forced into action for a third time just before the half-hour mark. Bedsente Gomis pounced on a loose, deflected ball in the box and the Leeds ‘stopper kept it out, but only with his backside. The ball then broke loose from underneath him, but he was spared further blushes by smothering it.

Kevin Amankwaah and Tyler Denton vie for the ball (Getty)

It was Dallas who finally registered an effort on goal for the visitors around ten minutes before the interval, but his attempted chip was easily pushed away by Sutton’s Ross Wormer. Leeds had, by then, successfully taken the sting out of Sutton’s play, but still lacked a significant threat in their own. The first-half ended as it had started, with Deacon inviting another eye-catching, one-handed save out of Silvestri.

When both teams re-emerged, there was a sense that Sutton may have missed their window of opportunity. Monk’s midfield looked to have finally got a grip on their industrious opponents, and Whitehouse soon went close with a deflected effort just wide of the far post. Yet Leeds’ newfound confidence was misplaced, and their downfall was their own doing.

Marco Silvestri looks readies himself for a shot from Maxime Biamou (Getty)

In what should have been a routine communication between full-back and goalkeeper, Lewie Coyle and Silvestri instead crashed into each other, the latter falling to the ground. Coyle, desperately attempting to atone for his mistake, then tripped the ever-troublesome Deacon in the box. The referee Stuart Atwell pointed to the spot and Collins nestled the ball into the bottom-right corner.

Leeds reassumed control in the middle of the park but were never assertive, and failed to convert their busy pressing and neat passing into opportunities. The introductions of Kemar Roofe and Hadi Sacko did nothing to help. Sutton, on the other hand, had no such trouble, always sensing that Monk’s shaken backline would present them with a chance to kill the tie.

Jamie Collins converts from the spot for Sutton United (Getty)

Such a chance almost fell to Craig Eastmond. The former Arsenal youngster, a dynamic presence throughout, looked set to test Silvestri again before he was brought down by Liam Cooper, the Leeds captain. The centre-half had already had his name taken by Attwell early on and his late dismissal made his side’s exit certain. Several tense minutes later, Monk, Leeds’ travelling support and one poor old master of ceremonies were all forced to accept defeat.

Sutton United: Worner, Amankwaah, Downer, Collins, Spence; May, Bailey, Eastmond (Traore 90+1); Deacon, Biamou, Gomis.

Subs: John, Fitchett, Gueye, Monakana, Tubbs, Shaw.

Leeds United: Silvestre; Coyle, McKay, Cooper, Denton; Grimes, Phillips, Dallas (Sacko 57); Whitehouse (Roofe 73), Doukara (Wilks, 64) Antonsson.

Subs: Peacock-Farrell, Vieira, Ayling, Vann.

Referee: Stuart Atwell