Van Gaal said: “What I can say, it [Mourinho’s departure] was a big surprise for me, I didn’t expect that that.
“He is a fantastic manager with a record that nobody has in this football world.
“But it is still possible. The main thing is always, of course, the results and second the chemistry between the players and the manager and his staff.
“I cannot judge what was happening at Chelsea but I was very surprised.”
Van Gaal, who insisted that the chemistry between himself and his players remains fine, added: “I have the full confidence of my board and my players, I feel.
“But we have to get results, we have to win, we know that – the players know it, I know it and my staff know it.
“We have to win because when you lose too much it’s the end of the world for me also.”
Fourth-placed United are at home to Norwich tomorrow when captain Wayne Rooney is expected to return from a three-match injury absence with an ankle problem to make his 300th appearance for the club.
“I hope when he plays he scores a goal because it is a big day for him because it’s his 500th game. Not too many players have reached that record,”