The game finished goalless but City had a great late chance to win it when Nicky Maynard burst through and the offside flag stayed down. However, the in-form striker stumbled as he went to shoot.
"We are disappointed," said Millen. "Considering it's a tough place to come and they are fighting for the play-offs, I would have taken a clean sheet before the game.
"But when you analyse the game we definitely had the clearest chances to win it and when you see Nicky go through with five minutes left you expect him to score.
"He's disappointed. That would have won us the game and I think we deserved the three points."
Source: PA
Source: PA