The youngster scored the winning goal against Hull City and earned himself a hat-trick on his U21s England debut, but is yet to start under the Portuguese boss.
He was sent on at half-time against Manchester City as Man United trailed 2-1 behind Pep Guardiola’s side and has impressed Mourinho, persuading the manager to play him in the Feyenoord fixture on Thursday.
“For me, the next big game is against Feyenoord and the next game he (Rashford) is going to play,” he said.
“That is the only thing I can say. I trust him completely. I know his future will be absolutely brilliant.
“He is mainly a No 9, but if you want to play him in different positions, we need to work him, we need to improve him. But his big personality is there.
“Normally, people look to the football talent, but the personality at this level is very, very important and he was showing that last season, he was showing that immediately.”
Henrikh Mkhitaryan and Jesse Lingard were hauled off at half-time after a disappointing first-half and Rashford managed to make an instant impact as he was introduced.
Rashford changed the whole dynamic of our attack and found himself a disallowed goal as it deflected off an offside Zlatan Ibrahimovic.
He would have undoubtedly impressed Mourinho and he has now been rewarded with the opportunity he deserved, to start his first game under the Portuguese boss.