Within three minutes of marking the first EFL game at the VBS Community Stadium with a first EFL win thanks to a David Ajiboye goal that sparked wild celebrations (above), Sutton were left without even the consolation of a point as for the second time this season an injury time goal condemned U's to defeat.
Hopes of the victory had already been dashed by Oldham skipper Carl Piergianni, scoring against U's for the third time in three games, when he headed his side level two minutes from the end of the ninety, but in the sixth of seven added minutes a swift counter attack from a Sutton corner ended with Junior Luamba driving a shot past Dean Bouzanis and this time the celebrations were from the Oldham supporters who had earlier sounded disillusioned as U's seemed set for victory.
Sutton were left to rue missed chances, dominating long periods of the game, and in the first half particularly U's created enough to go in at half time in control, but although Ajiboye eventually found the breakthrough it left U's with only a single goal lead to defend and an Oldham side who had created little somehow found a way to win the game and send U's to the foot of the embryonic League Two table.
The excitement was tangible as U's finally played an EFL game in front of home supporters, and the start matched that enthusiasm as Louis John and Omar Bugiel sent headers just too high inside the first ten minutes before Enzio Boldewijn, starting in place of the unwell Kenny Davis, cut in from the left and curled a shot just past the post.
Forced in to an early change when left back Sam Hart was forced off injured, Oldham rarely threatened, although Dylan Bahamboula showed his quality with one fine run and a shot over the bar, but it was U's who had much of the play and a Donovan Wilson cross was scrambled away in the six yard box before he miscued a shot high and wide after a storming run from Bugiel. The best chance, though, fell just as the reserve official was holding up the board showing additional time at the end of the first half, as Ajiboye's incisive run ended with a pass to Boldewijn, whose shot deflected in to the air of a defender and fell nicely for Ajiboye, who had continued his run but put an unchallenged header over the bar.
Oldham made another change at the break, Davis Keillor-Dunn replacing Harry Vaughan, and when Dylan Fage limped off five minutes later they had made all their changes and were on to their third left back. They might have been behind by then, Wilson heading over following a long throw while Ajiboye had penalty appeals waved away by referee Darren Drysdale, who instead booked U's winger for simulation, but just after the hour mark came the goal that U's craved, and deserved. Rob Milsom's cross was scrambled away as far as Craig Eastmond, whose superbly struck twenty yard effort crashed down off the bar but Ajiboye was on hand for the rebound and although his first shot hit Jordan Clarke, his second hit the back of U's new amber net.
Bettache, who had replacd Fage, joined Bahamboula as a threat for Oldham, although when he had shooting opportunities they were some way off target, but U's had chances to kill the visitors off, Bugiel shooting over after being set up by Wilson, who then had a shot blocked after he was forced slightly wide after a good run where an early ball to Boldewijn might have been the better option.
The fragility of the one goal lead was hammered home two minutes from time when Keillor-Dunn took on Ben Wyatt, who had replaced the injured Milsom, and fired in a cross that was met by Piergianni's head and the ball hit the post and bounced in behind Bouzanis, adding to the two goals that Piergianni had scored for Salford in the two games against Sutton in the 2018-19 season.
With seven minutes of stoppage time indicated there was time for either side to win, and when Bugiel forced a corner off Piergianni with five of those played it seemed as though the afternoon might have the dramatic finale to suit the occasion. It did, but not in the way U's imagined as Piergianni headed the corner away and Bettache set Bahamboula off on a run that evaded Jon Barden's attempt to block him and ended with another exchange with Bettache before a shot that looped up in the air and fell via Keillor-Dunn to Luamba, who moments earlier had been booked for a lunge on Ben Goodliffe but who now gave Bouzanis no chance with a low shot that won the game.
Sutton: D Bouzanis, J Barden, R Milsom(sub B Wyatt 67), C Eastmond, B Goodliffe, L John, D Ajiboye, D Wilson(sub R Korboa 90+3), O Bugiel, H Beautyman, E Boldewijn(sub A Smith 85). Subs n/u B House, C Rowe, J Kizzi, R Bennett. Booked: Ajiboye, Eastmond.
Oldham: J Leutwiler, R Diarra, S Hart(Sub A Sheehan 17), D Fage(sub F Bettache 50), J Clarke, C Piergianni, H Vaughan(sub D Keillor-Dunn H-T), C Whelan, H Hope, J Luamba, D Bahamboula. Subs n/u K Danielewicz, N Adams, Z Dearnley. Booked: Diarra, Piergianni, Luamba.
Referee: Darren Drysdale
Attendance: 3,262 (457 away)