The Liga title holders are due at Old Trafford on Wednesday for the first leg of a heavyweight quarter-final clash.
Ernesto Valverde’s side have been in impressive form again this season, with their mercurial Argentine forward leading the way after blasting through the 40-goal barrier once more.
United have been warned that trying to contain Messi is a thankless task, but Mata believes Ole Gunnar Solskjaer’s side are capable of holding their own against Barcelona as a collective.
The Spaniard told the Daily Star of the challenge facing the Red Devils: “We are Manchester United and we are representing one of the biggest clubs in the world.
“Fear is not the word. Respect is the word.
“We also have to trust ourselves and know that if we have a good day we can give them a game.
“That is what is in our minds to try to do it well and fight for our fans and our club.
“Barcelona is a fantastic team, one of the best teams in the world.
“We are really looking forward to having a good round and hopefully qualify.
“Obviously they are in a good moment and they are top of the table in Spain but we are confident that we are Manchester United and we can have two good games and we can qualify.
“It’s those games that you are a football player for.
“You want the important games on the biggest stage which is Old Trafford, Champions League quarter-final so we are looking forward to it. Hopefully, it will be good for us.”
United head into a meeting with Barcelona coming off the back of three defeats in their last four outings across all competitions.
Confidence has, however, been restored to the camp since Solskjaer took the reins, leading to him being handed a three-year deal.
The notable scalp of Paris Saint-Germain has already been collected in Europe, with it hoped that results such as that will help to convince the likes of Mata – and the rest of those locked in contract extension talks – to stay put.
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