Manchester United clash with the Spanish giants at Old Trafford on Wednesday night in the first leg of the quarter finals.
Barca are red-hot favourites to go through over two legs and end United’s European dream for another season.
The Ernesto Valverde’s men are romping to the La Liga title and have not tasted a single defeat in Europe this season.
But Mata reckons the regular presence of Fergie at the training ground will lift his team-mates and remind them what United stands for.
New boss Ole Gunnar Solskjaer has also been making his squad watch videos of some of United’s most famous European nights under Fergie.
Like the one Solskjaer starred in himself, when his goal in Barcelona of all places, helped United win the Champions League and treble in 1999.
Mata believes delving into the past can help United secure a bright future in the competition and he said:
“I’m sure (Solskjaer) will do this in the next days. We will have in our minds his image, celebrating that goal and Sir Alex Ferguson celebrating.
“I was young and some of my teammates were probably not watching TV at that time!
“But it was a fantastic memory for a lot of people that love Manchester United in that stadium.
“For himself also, scoring that goal. So I’m sure he will speak about it, his most important goal. We will try to make another great night for Manchester United fans and create new and very good memories for them.”
Fergie’s appearances at the Carrington training ground have been welcome for Mata and he added:
“The times that he was there in the last months, he was just watching training and he would say ‘hello’ to everyone and would have a longer conversation with the manager than the players.
“But having him there, his aura, his memories, what he’s given and done for this club is something you cannot really explain.
“Obviously it’s very nice when you see he has recovered from what he had (brain hemorrhage).
“He’s one of the most important figures in Manchester United and when he’s close to us, he gives you that positive energy.”