"It was a very resolute performance," Cooper said after the game.
"On Saturday we conceded a couple of needless goals but tonight the goalkeeper and centre-halves were outstanding.
"When you're in the position we're in and you come here, with the players they have, you have to respect that.
"We have to build on this. We mustn't think we can just turn up and it'll happen for us at Coventry on Saturday."