But this season, they are once again in the Europa League. And after a 1-1 draw with FC Twente, the "Red Devils" showed all the qualities of a Europa League team.
Twente are currently fourth in the Eredivisie and one of the lowest seeds in this season's Europa League. They will be delighted with the draw against Man United. Meanwhile, the 4,000 Twente fans at Old Trafford celebrated as if they had won.
This will be a timely warning for Erik ten Hag ahead of three important games against Tottenham, Porto and Aston Villa. If things don't go well, questions surrounding Ten Hag's position will start to arise again.
Ten Hag said he did not want to face his former club because "it's not nice to hurt something you love". In the end, it was Twente who caused Ten Hag pain.
"We let them take control of the game when we were 1-0 up. We didn't score a second goal to kill the game. And then we were punished for our own mistakes.
"It was a collective mistake. Twente's players could dribble the whole pitch without being stopped. We were too complacent, the players lacked ambition in the second half and paid the price," Ten Hag said after the match.
Playing in the Europa League in his third year at Old Trafford may not have been in Ten Hag’s plans. But whether he wanted it or not, he needed competition at this level. Under constant pressure after finishing eighth in the Premier League last season, Ten Hag was smart enough to know that he was in no position to give up any competition.
And while Ten Hag wanted to rest key players like Diogo Dalot and Bruno Fernandes, he couldn't afford to take any chances. In the second half, the Dutchman was forced to bring on Rasmus Hojlund and Mason Mount, both of whom had just returned from injury, in search of a goal.
For now, United need to get through the early stages of the new format. Perhaps by the time the knockout stages come around in February next year, Ten Hag’s side will be in such a good position in the Premier League that the Europa League will no longer be a priority.
However, at the moment, that luxury is not there. They need results and performances in every competition, especially the one that has the chance of returning to the Champions League.
A return to Champions League contention alongside the likes of Real Madrid, Bayern Munich and Manchester City is surely the bare minimum required in Ten Hag's first year under Sir Jim Ratcliffe.
To do that, the "Red Devils" need to score more goals. After failing to score in the draw with Crystal Palace, Man United fired 19 shots against Twente but only had a first-half goal from Christian Eriksen. Their record in the Premier League is also just 5 goals in 5 games.
Man United are one of the favourites to win the Europa League this season. With no teams relegated from the new Champions League format, their biggest challengers are Tottenham, AS Roma and Eintracht Frankfurt.
At the end of the season, Ten Hag hopes United can once again call themselves a Champions League team, no matter how they get there. But now the Old Trafford outfit will have to settle for the Europa League. And Twente have proven that, for now, United belong in the competition.
