The Manchester City manager clashed angrily with Liverpool skipper Steven Gerrard after the 1-0 Carling Cup defeat. Still fuming at Kompany's appeal being turned down yesterday, Mancini feels there was a clear lack of consistency in Johnson not even getting booked for his two-footed challenge.
"It was worse," he said. "This tackle was worse. Gerrard came to me and said I said something. It was not for Johnson. It is for the tackle. This tackle was worse than Vinny's. Everyone can see it."
Mancini clashed with Gerrard twice, the second particularly fractious, although the Liverpool goalscorer was unrepentant.
"It surprises me because he had a go at Wayne Rooney. Now he's had a go at one of ours," Gerrard told BBC1, in response to comments from Mancini claiming the England striker had influenced the decision to dismiss Kompany.
"Steven Gerrard can say what he wants," Mancini responded.
"I said what I think. That is what I am used to doing. It is not important what Steven Gerrard or the other players have said."
The incident completed a bad night for Mancini and his team, who were suffering back-to-back home defeats for the first time since February 2008.
Kompany's stand-in Stefan Savic had a particularly difficult time, struggling to contain Liverpool forward Andy Carroll and conceding the penalty that allowed Gerrard to ram home the winner when he caught Daniel Agger.