Marcus Rashford winning fitness battle - Ole Gunnar Solskjaer

Rashford, who has been managing various injuries in recent weeks, missed both of England's Euro 2020 qualifiers in March as well as United's 2-1 league defeat by Wolverhampton Wanderers last week but was part of Tuesday's training session.

"He needed the extra warm up, hopefully he won't get a reaction. He couldn't join the boxes which is the fun part of training, let's see tomorrow. Hopefully he'll be ready," Solskjaer told a news conference.

United are also sweating on the fitness of Nemanja Matic, who was on the bench against Wolves due to a muscle issue while fellow midfielder Ander Herrera is a doubt with a knock. Striker Alexis Sanchez trained for the first time with the squad since overcoming a knee ligament injury, but Wednesday's meeting with his former team comes too soon for him.

"He's done lots of recovery work. He's injury free. He'll probably be in the squad for West Ham United (in the Premier League) on Saturday. He's not going to be able to join in tomorrow," Solskjaer added.

United were beaten 2-0 by Paris St Germain in their round of 16 first leg at Old Trafford before sealing a memorable 3-1 win in Paris to progress on away goals. Solskjaer is aware of the need to avoid a similar blip at home against Barcelona.

"We know we need to perform to our best levels, which we didn't against PSG at home. The outcome of the second leg gave the players and supporters belief," the Norwegian said.

"When you get Barcelona, with the quality of their team, we know we need to step up our game.

"The Champions League throws up strange results. It's not going to be decided until we play 90 minutes in the Nou Camp. We just have to make sure we perform to our best and have a result to take over to Barcelona."