- Scott McTominay (90'+3')
The Red Devils needed a second-half rally to beat the Cypriot First Division club last Thursday, but were left frustrated throughout in the reverse picture despite dominating possession and chances in the game.
Erik ten Hag's United saw Marcus Rashford kept out with only Omonia keeper Francis Uzoho to beat, a Casemiro rocket tipped off the crossbar in the 32nd minute and Fred loop a header over the goal from a good position in a scoreless first half.
It was more of the same in the second half for United as boos rained down from the stands at Old Trafford, until McTominay popped up in stoppage time to bail his team out with a finish from the centre of the area after the ball fell kindly at his feet.
"In this team there is a lot of creativity and scoring capabilities," Ten Hag said after the match. "Sometimes you have a night where you will not succeed. Today was that night.
"But the good thing was the team keep going and they don't give up. They keep believing and in the end we get the reward. That is the way we have to do it."
The win leaves Man United, who took 34 shots on the night, in second place in Group E on nine points from four games, three behind leaders Real Sociedad with two matches left to play.
"I am really happy with [the result]," Ten Hag added. "It is about the spirit in the team and the squad. It is not just about the 11 players. Sometimes it works like that. Substitutes can have an impact when they have the right attitude and the right focus."
- Jerome Brisard