Manchester United want to take all three points today and delay Leicester City's party, manager van Gaal said.
The Red Devils are still fighting for a Top Four and desperately need all three points after Arsenal battled past Norwich City on Saturday afternoon.
Defender Luke Shaw continues on the sidelines as he continues his recovery ahead of the FA Cup final in May.
"We don't have any injuries, except [Luke] Shaw, who is already not injured any more but is building up, and [Bastian] Schweinsteiger," van Gaal said.
"He [Luke Shaw] can [face Crystal Palace in the FA Cup final], maybe, but it shall be difficult because he has to play first a lot of matches in the second team.
"We have to wait and see because you cannot say anything. It's going very well with him.
"I think we have to beat Leicester because we are still in the race for the first positions, so we have to beat them.
"We cannot allow that they are the champions this weekend at Old Trafford. I think they shall be the champion a week later, so we don't spoil the party, just postpone it a little bit.
"I was the first who said that they could be champions and now a presenter [Match of the Day's Gary Lineker] has to wear underwear when they are the champions. For me it is not a surprise; I say that many, many times. I believe in team building and the manager has done that with this team.
"They had the circumstances to play always with the same team as they did not play so many matches as the other teams in the league, so it is always possible. It is good for the Premier League and the sport of football that not always the same teams are the champion."