United head to Spain with a 1-0 deficit after Luke Shaw deflected in Luis Suarez’s header at Old Trafford last week.
It’s not beyond Ole Gunnar Solskjaer’s men though, who went to PSG in the previous round 2-0 down from the first leg and progressed.
The away goals rule is in action for the Champions League, meaning a very specific result is needed to take the game to penalties tonight.
If the scores are level following 180 minutes the team who scored more of the goals away from home go through – however if both teams scored the same number of goals home and away then it goes to extra time.
The away goals rule can also come into play in extra time if all things are level again but more goals have been scored in the added 30 minutes.
However if the teams still cannot be split then the match goes to penalties.
It means that the only way Manchester United’s trip to Barcelona can go to penalties is if United are 1-0 winners in the 90 minutes tonight, and it stays that way through extra time.
Solskjaer though is hoping it doesn’t have to come to that, and is drawing inspiration from the remarkable turnaround against PSG.
“It will have helped us as a team,” the Norwegian said.
“We know we can turn things around.
“Barca here at the Nou Camp is a difficult prospect but that night will live with the players.
“It was not that long ago and we are one goal better off [than we were then].”
Manchester United go into the clash with Barcelona with plenty of news surrounding the Red Devils:
And Barcelona boss Ernesto Valverde also knows the tie isn’t done and dusted just yet.
“The result from the first leg is not definite,” he said.
“We have to play our own way. We will try to make sure they don’t score. We want to win the game.”