Rashford was handed his United debut by Van Gaal against FC Midtjylland last season.
The 18-year-old went on to score twice and has not looked back since, continuing to impress under Mourinho this season.
And the teenager has now revealed how Mourinho’s methods differ to those of Van Gaal.
“Van Gaal’s sessions are directly related to the games, whereas Mourinho is more about making players complete players,” Rashford told Sky Sports.
“They are different and take getting used to, but everyone is relishing it.”
Rashford added he hopes to follow in the footsteps of Cristiano Ronaldo at Old Trafford.
"In recent years Ronaldo is the example, wherever you put him in the attacking three he's going to make an impact and the opposition are going to fear him,” the teenager added.
"Being a constant threat, that's what I need to develop.
"(Wayne) Rooney and Ronaldo were unreal. In 2007/08 it was an unreal partnership, they have been huge players I have looked up to and watched how they perform to try to put into my own performance."