Man United fans chanted his name at Old Trafford after his turn around just six weeks on from when he conceded a late penalty in a 1-1 draw at Everton.
He was jeered again when he joined United’s 1-0 win over Tottenham at Old Trafford as a late substitute and has endured a touch time since his arrival on deadline day in 2013.
Speaking about the Belgian, Mata has revealed how the United dressing room rallied round Fellaini to help make their team-mate feel loved.
“I’m very happy for Marouane because he’s had difficult times since he came to the club,” he said.
“But he’s a great guy, he’s a great person, he always trains the best he can and I’m delighted for him.
“It was an important goal for him and everybody was happy for his goal. When a team-mate is not in the best situation and it’s difficult for him, we have to be there to support him.
“I think this will be a boost for his confidence. It was good to hear the stadium singing his name because he deserved it.
“He’s a strong man with experience. He’s not a young player, he’s 29, so he’s lived so many things in football.
“But it’s not nice when you play in your own stadium and you don’t have the best atmosphere.
“But now it’s different and it’s changed. I think it’s going to be positive for him in the future.
“It makes it easier for you as a player when you feel the confidence of everyone. You feel an even better player.
“Confidence is very important for any player and hopefully Marouane now has his back.
“He always gets on very well with everyone. Since I came here he was a good friend of mine and everyone in the dressing-room.”
Fans have seen him as a symbol of Moyes’ failed short reign at Old Trafford and although the situation didn’t improve under Louis van Gaal, Mourinho has been set on turning that around.
The Portuguese boss has placed his faith in Fellaini and has even triggered a one-year extension option on Fellaini’s contract, and it remains to be seen how much of a impact he’ll have at Old Trafford.