Chopper reviews Tuesday night's narrow loss at the Pirelli Stadium
Harris admitted after the game that he felt 'harshly done by' in a match that saw some key decisions go against his team, who finished with 10 men following the injury-time dismissal of Mark Beevers for two bookable offences.
"A draw probably would have been a fair result," said Chopper. "We dominated a large part of the first-half but conceded two very unprofessional goals.
"The decision to disallow Aiden's goal probably changed the course of that first-half, which was frustrating, but I was pleased with our reaction after half-time. We were much better in the second-half.
"I spoke to the referee after the game and he is a good referee; he told me that there was contact with Aiden in the penalty area in the second-half, so I find it hard to understand why it wasn't a penalty, but I respect his decision. He has to make it quickly, but it was a big call.
"The sending off looked very harsh. Mark Beevers was looking at the ball all the time and I'm not sure how he could avoid the player. This is probably the first time since I became Millwall manager that I have had to say that I felt we were a bit hard done by.