A depleted Sutton side fell to a second consecutive Sky Bet League Two defeat for only the second time this season at The County Ground, Swindon repeating the 2-1 success that they had enjoyed in both previous meetings between the sides.
It was a disappointing outcome for U's, who battled hard but conceded two avoidable goals and as a result dropped out of the top seven in what is still a very tight battle at the top of the table, the late dismissal of Louis Reed for a second bookable offence coming too late to give U's time to take advantage.
The ten players ruled out through injury included every central midfielder, with Adam Lovatt recalled from his loan at Tonbridge to play alongside Omar Bugiel, while Enzio Boldewijn started up front alongside Richie Bennett, and Ben Goodliffe became the sixth player to take the captain's armband this season.
Unsurprisingly Swindon started the better, and Stuart Nelson had to make an early save from Harry McKirdy when the lively winger, returning from suspension, cut in and hit a low shot which Nelson saved with his legs, but it was from Sutton's first attack that Swindon took the lead. David Ajiboye drifted in from the right past three challenges with a fine run which ended with a shot deflected for a corner, but it was Swindon who profited as JoJo Wollacott collected Will Randall's corner and delivered a long clearance downfield. Nelson decided to come outside his area to clear but paid for slight hesitation as he was beaten by Josh Davison, who lifted the ball over the keeper and then drove it past the covering Ben Goodliffe in to the net.
U's faced a difficult spell as Davison and Ellis Iandolo both went close in the next five minutes, Davison volleying McKirdy's cross just wide and Iandolo sending a cross shot wide, and it looked as though U's might face a long night but the storm was ridden out and, after Richie Bennett had been fouled by Dion Conroy, Joe Kizzi met Enzio Boldewijn's free kick with a downward header in to the far corner, his run perfectly timed to survive the offside claims.
Having had the first half hour pretty much their own way, Swindon were rattled by the equaliser, and Louis Reed was booked for a challenge on Kizzi, referee Carl Boyeson playing advantage and then giving the free kick when Boldewijn was fouled ten yards further forward. This time Bennett tried his luck from the dead ball, and Wollacott uncertainly pushed it away for a corner.
Boldewijn then sent a low shot just wide after taking advantage of some hesitancy in the home defence, but the home side did have a chance just before half time when McKirdy shot over at the end of a move he had started himself with a crossfield run, but U's will have been the happier to hear the half time whistle.
Four minutes in to the second half, though, the home side had regained the initiative as, after Bugiel had been penalised and Boldewijn booked for delaying the free kick, Conroy then sent the ball long down the left for Jonny Williams, whose low cross was turned in by McKirdy as this time U's looked for an offside flag that didn't come, McKirdy possibly just behind the ball when it was played.
It was slightly against the flow of the early part of the second half, but apart from a Bennett header that he was unable to direct U's struggled to create anything clear, and it was Swindon who came closest to changing the scoreline, Williams shooting just wide from twenty yards and McKirdy's low cross shot pushed away by Nelson.
Kylian Kouassi replaced Bennett with just under twenty minutes to go as U's looked for a way back, and one was nearly found as Lovatt's low volley from the edge of the penalty area was just too close to Wollacott. Boldewijn was just unable to reach a header from Kizzi, following up after his first cross had been cleared, but the equaliser wouldn't come, although U's had claims for a stoppage time penalty turned down when substitute Mandela Egbo seemed to block a Bugiel shot with his arm, albeit at close range. As U's were appealing, McKirdy beat Ben Wyatt to the clearance and raced in to the penalty area, evading Wyatt's challenge but denied by a fine piece of goalkeeping by Nelson diving at his feet. As the ball ran loose Reed went over as Nelson challenged again, with referee Carl Boyeson deciding that the midfielder had dived and showing a second yellow card.
U's immediately brought on Craig Dundas for Goodliffe, but there was insufficient time for U's to take advantage of the extra player as Swindon held on fpr the points.
Sutton: S Nelson, J Kizzi, B Wyatt, C Rowe, B Goodliffe(sub C Dundas 90+5), A Lovatt, D Ajiboye, E Boldewijn, O Bugiel, R Bennett(sub K Kouassi 72), W Randall. Subs n/u B House, R Korboa. Booked: Boldewijn, Rowe
Swindon: J Wollacott, A Odimayo, E Iandolo, D Conroy, R Hunt, M Baudry, J Williams(sub M Egbo 83), L Reed, J Davison, R Aguiar(sub J Payne 60), H McKirdy. Subs n/u L Ward, J Mitchell-Lawson, R East, H Parsons, H Minturn. Booked: Reed, Iandolo,Davison. Sent Off: Reed (second bookable offence).
Referee: Carl Boyeson
Attendance: 8,243(112 away)