Peterborough boss Darren Ferguson felt his team’s display was “nowhere near good enough” as they were beaten 3-0 by the Blues at the Weston Homes Stadium.
Wes Burns, Conor Chaplin and Freddie Ladapo scored the goals as Town recorded their first ever league win at London Road.
"We were nowhere near good enough to win a game of that magnitude,” he told the Peterborough Telegraph. "We needed an eight out of ten for everyone but today we just didn’t do that.
"I’m really annoyed and disappointed that we didn’t perform better on the big stage and it looked like we’re so inferior to them. Today we were but I don’t like that because I don’t think that’s the case.
"We have to find a way of getting a bigger desire to win these games. We need more fight and character. We played well for maybe 15 minutes but we were 2-0 down, it’s too late then.
"We didn’t deserve anything out of the game, I’ve seen too many performances like that now at this place, I don’t like it.
"We have to be stronger mentally, we have to be better on the ball and we have to be braver.
"We’re better than that, it was just like the Derby game in the first half, we were all over the place until we changed things.
"We have to be better than this in these kinds of games, this is what we’re in it for. These are the games you have to enjoy.
"We never got any control, they had so much more composure. We didn’t win enough headers or second balls.
"The goals are horrendous. You can have a bad game but to concede from a throw-in and then the third one, it’s just gone into the box, the centre-half has missed a header and the other one has been bullied out of the way.
"The second one, Hector [Kyprianou]’s got the ball, there’s no one anywhere near him and he boots it out of play and they go up the pitch and score. That sort of thing happened too often today.”
Ferguson was annoyed by referee Gavin Ward's decision to book Oliver Norburn for chopping down Sam Morsy, having eventually been forced to substitute the midfielder at half-time after the former Shrewsbury man had later been spoken to at length by the official.
He added: "If Ollie or any of my players go and top someone or make a horrendous challenge I’d be more frustrated but when he’s got booked for that, I can’t. The referee wanted to make it about him.
"He then sets a precedent that he’s got to book everyone. Morsy had five fouls before he got booked. I’m disappointed that I’ve got to bring him off because I’m worried he’s going to get sent off.
"It’s a poor decision and he was the only one that was tackling. You’ve got to tackle in a game of football. We didn’t win enough tackles, headers or second balls.”