Sutton shrugged off the disappointment of Wembley with a battling win that kept U's in the hunt for the Sky Bet League Two play-offs.
Supporters who were at the last home game against Tranmere three weeks ago could have been forgiven for a sense of deja vu as U's dominated the first half with only Joe Kizzi's fifth league goal in eight games to show for it, and were then on the back foot for long periods of the second half as Leyton Orient pushed for an equaliser, but unlike against Tranmere U's held firm, and this time even survived seven minutes of stoppage time, despite the board showing four at the end of the ninety minutes.
U's efforts at Wembley had taken their toll, Ben Goodliffe and Will Randall ruled out with injury and Donovan Wilson was also absent after reporting ill on Saturday morning, but after a quiet start to the game it was U's who took charge of the game and were almost ahead when an inswinging free kick from Rob Milsom just eluded the lunging Louis John and was pushed away by Lawrence Vigouroux, with Isaac Olaofe heading over from the resulting corner.
Dean Bouzanis was called in to action for the first time to save a shot from Aaron Drinan after a poor headed clearance from Craig Eastmond, but four minutes later a fine piece of anticipartion from Milsom set up the crucial moment as he broke up an Orient attack and linked with Enzio Boldewijn on the left before crossing for David Ajiboye, whose layoff gave Harry Beautyman the chance to fire in a shot that was tipped over by Vigouroux. The keeper tipped away the resulting left wing corner for another, this time on the right, but was nowhere near Milsom's delivery as Kizzi's header bounced in to the unguarded net.
Bouzanis made one good save from Paul Smyth's low shot, pushing the shot against the outside of the post, but U's were still in charge and were almost gifted a second when, trying to play out from the back, Vigouroux passed the ball straight to Boldewijn, who was slightly too slow to react and allowed Dan Moss to block his shot, Richie Bennett sending the rebound wide.
Bennett went close again just before the interval as another Milsom free kick fell to him in a goalmouth scramble and he poked the ball goalwards, only for Vigouroux to make a fine save to push the ball over.
The second half was a different story as Orient took advantage of the wind being behind them and began to cause U's problems. Coby Rowe blocked a fierce shot from Smyth that looked goalbound, and John managed to prevent Theo Archibald getting a shot in as U's found it hard to get the ball over the halfway line, and when Omar Bugiel replaced Bennett just before the hour mark his first involvement was to pick up a booking for a foul that prevented an Orient attack.
Having scored what would prove to be the winner, Kizzi made an equally important intervention at the other end when Drinan broke in to the penalty area on the right and crossed for Smyth, whose shot was blocked by the challenging Kizzi. Sky Bet League Two Player of the Month Ruel Sotiriou came on midway through the half, his first involvement about as notable as Bugiel's as he sent a shot from the edge of the penalty area high over the bar.
Both Archibald and Otis Khan sent shots from outside the penalty area just wide as Orient continued to press for an equaliser that wouldn't come, but they couldn't keep up their momentum as U's managed the game well, the visitors' frustration bringing bookings in the closing stages for Archibald, Beckles and Khan. There was a welcome return for Ali Smith with twelve minutes to go, and it seemed almost cruel on U's that, with four minutes shown as additional time and mainly due to a brief altercation between Olaofe and Vigouroux, referee Robert Lewis allowed the extra time to run on to almost double that, but there were no repeats of the Wembley misadventure and U's were able to celebrate a victory that keeps the play-offs well within reach.
Sutton: D Bouzanis, J Kizzi, R Milsom, C Rowe, C Eastmond, L John, D Ajiboye, I Olaofe, R Bennett(sub O Bugiel 56), H Beautyman(sub A Smith 78), E Boldewijn. Subs n/u B Wyatt, K Davis, R Korboa, K Kouassi, S Nelson. Booked: Bugiel
Leyton Orient: L Vigouroux, J Sweeney(sub D Nkrouma 84), D Moss(sub M Young 75), O Beckles, S Ogie, O Khan, P Smyth(sub R Sotiriou 67), D Pratley, A Drinan, H Kyprianou, T Archibald. Subs n/u S Sargeant, F Nouble, J Brown, G Ray. Booked: Kyprianou, Archibald, Beckles, Khan
Referee: Robert Lewis
Attendance: 3,152(452 away)