"I felt 3-0 flattered Portsmouth but two goals in four minutes killed the game," he said.
"I could tell from the Portsmouth bench that they were worried but then we missed a great chance and the game had gone.
"We have to learn to be more ruthless and be prepared to upset each other in the team's cause.
"Our problem is that we are too nice and must be prepared to get stuck in.
I have a great set of lads but they must be more nasty."