Ole Gunnar Solskjaer admitted Manchester United were handed a “reality check” after his first defeat since taking charge.
United were outclassed by Paris St Germain, with caretaker boss Solskjaer conceding there was a gulf in class between his side and the French champions.
PSG were inspired by France World Cup winner Kylian Mbappe, who scored the second goal, while United flop Angel Di Maria responded to taunts from the Old Trafford crowd with two assists.
Solskjaer admitted United have it all to do to overhaul a 2-0 deficit in Paris on March 6 but said: “Mountains are there to be climbed. You can’t lay down and say this is over.
“We will go there, play our game and improve from today. But today was a reality check for us.
“You could see that we hadn’t played at this level for a while and we will have to learn. It was an experience that can go either way. It’s not going to be a season defining one, it’s one we have to learn from.”
United will be without Paul Pogba for the second leg after the in-form midfielder was sent off for a second yellow card late on after clashing with Dani Alves.
“Paul was trying to get his body across and Alves is clever enough to put his foot in there,” said Solskjaer. “Paul wants to shield the ball and he’s unlucky.”
Solskjaer vowed United will bounce back from their first defeat under him and said any player feeling sorry for themselves will not start Monday’s FA Cup tie at Chelsea .
“I’ve told the players not to feel sorry for themselves,” said Solskjaer.
“Look forward – we’ve got Chelsea and Liverpool next two games. Anybody feeling sorry for themselves probably won’t play against Chelsea.
‘At this club you bounce back. You have to bounce back. The Champions League is always going to be difficult, but we have the Premier League and the FA Cup. There is a desire and determination to put this right. We will go to Paris to give it a go.’
United suffered a double injury blow when Anthony Martial and Jesse Lingard were both forced out of the game at half-time with muscle injuries. Both could now miss the trip to Stamford Bridge.