The Portuguese boss took over at Man United in the summer and immediately showed the Belgian his backing by providing him with a much-needed confidence boost before the start of the season.
He has made regular first-team appearances under both managers, but has only showcased his worth on the side to supporters under Mourinho this campaign.
Speaking about the pair, Fellaini revealed van Gaal’s methods were much stricter than Mourinho’s.
“It is funnier with Mourinho, the training changes all the time. It is not a routine. Van Gaal had his philosophy and he was strict but he was very different.
“I think Mourinho is the right manager. He has a lot of experience and he knows what he can do but you have to give him time as well so I’m sure the victories will come.
“He’s asked me to play my game. He knows what I can do. Straight away, he said to me, ‘I know you’re quality, I know what you can do.’ During the Euros, he called me and asked if I wanted to move or continue so it definitely gave me a boost.
“I think we started well. We lost two games and I think the problems started but that’s football. In British football, every game is difficult. It is a big pressure. That’s football at the biggest club, that’s why, but I think we have to keep working and we will win games I’m sure.”
Mourinho had played Fellaini alongside Paul Pogba at the start of the season and although the pair formed a solid partnership, the boss soon realised there were other players on the side that could do a better job.
He recently identified Fellaini as Pogba’s natural replacement and it seems he could still have a big role on the side, but it’s heavily dependant on our opponents.