Rafael's wonderful first-half drive and Ryan Giggs' strike 10 minutes from time helped United secure a comfortable win over the bottom club.
Redknapp's side now have just 11 matches to claw themselves off the bottom of the table and out of trouble.
But Redknapp still believes his side can stay up and said: "I thought we were bang in the game.
"The little right-back hits a `worldie' - he won't hit another goal like that as long as he plays football. He's hit one out of the clouds that's gone in the top corner. Up until then there wasn't a lot in it.
"This leaves us bottom but we won't be bottom at the end of the season. I still feel we'll get out of it.
"Every game is important, they will be tough games.
"We need to get a team together on Monday, bed them in and work with them, and I think there's enough there to give us an opportunity. I'm still optimistic.
"You probably think I'm mad but I don't think I am. Everybody else has written us off but I haven't. I still feel we have a chance."
