"It was a poor quality performance, so lethargic," he told the clubs official website after the game.
."Cambridge will go home disappointed that they've lost. In reality, apart from the last 10 minutes, they didn't create too much in front of goal, they lacked a cutting edge. But, let's be fair, we're lucky to get through tonight and our players know that.
"I think the fans got us going towards the end of the match and, eventually, Andy Ferrell's goal papered over some cracks for us by getting us the all-important result in the cup."