Crouch almost missed the Chelsea victory with a virus but is hoping to be at full-tilt to face United.
Crouch said: "I was lucky to be on the bench against Chelsea, I didn't train on Friday and stayed at home.
"If we can get into the Champions League it will be a huge achievement. If we can do that and build on it that would be great. You've got to stay there. I've been fortunate to play in it and it's the best competition in the world.
"A club like this deserves to be there and hopefully we can get there and then obviously the top clubs have the consistency to stay there and we need to do that."