He said: "It was a tough game and we knew that it was going to be, we started slowly and conceded from a corner in the first few minutes.
"We grew into the game and their goalkeeper was excellent, they will be coming here full of confidence after a win at the weekend.
Rovers go into the game on the back of a 2-1 victory over AFC Wimbledon, and McCann says that result has lifted the mood in the dressing room.
He added: "It's been a frustrating run of results for us so it was good for us to get a win when we weren't at our best.
"We can focus on the cup for now and make sure we get through, we want to play with an identity and on the front foot.