The former England international believes they have nothing to fear from the fallen giants.
Crouch said: "It's last eight of the cup, Man United at home so everyone is looking forward to playing in that atmosphere for a chance to get to a semi-final.
"We can be confident. We gave a good account of ourselves at Old Trafford (a 3-2 defeat in October), when we were unlucky not to win or at least get a point.
"Hopefully we can play as well as we have been, and as well as we played to beat a full-strength Chelsea side last time at the Britannia.
"I don't know if United will rest players but either way, if we can beat a full-strength Chelsea side at home we can beat anyone."