Juan Mata punished Sebastien Bassong’s error as a 1-0 victory at Carrow Road saw United move within one point of neighbours Manchester City, who play Arsenal on Sunday.
Suddenly everything is looking more positive for Van Gaal, whose position has been under scrutiny for much of the season.
The Dutchman could yet guide United into the Champions League and FA Cup glory.
“We did our job today. Fantastic, I think,” Van Gaal said.
“When you see the second half, we deserved to win. We’re still in the race (for the top four).”
Van Gaal remains aggrieved at the failure to award United two penalties in the draw with champions Leicester a week ago, believing it cost United points to leave his side relying on the Gunners.
“Now we are dependent on Arsenal,” he said
United were without Anthony Martial at Carrow Road after the striker felt a twinge in his knee in the warm up and Van Gaal was not prepared to risk the Frenchman.
Martial, who joined the rested Daley Blind and Marcus Rashford on the sidelines, was replaced by Ander Herrera, pushing Wayne Rooney up front.
Rooney, who has been playing in midfield of late, laid on the decisive goal for Mata.
“I don’t think he was very happy with me that I decided to put him in the striker’s position, but he could imagine also (why he had to play there),” Van Gaal said.
“He gave a fantastic assist to Juan Mata.”