The Fulham chief went to shake hands with the man who succeeded him as City boss following this 1-1 draw.
But Mancini, who knew he had the Eastlands job before Hughes was even sacked in December 2009, did not appear very interested and Sparky pointedly pulled his hand away.
Mancini said: "I don't understand what happened, I don't know. I don't understand what he said.
"There was nothing during the game. But maybe I was like him in London because he did the same there.
"I don't know. He should be happy he got a draw against us but it's not important. The result is more important than these stupid things.
"To me it was not important, for you it probably was the best thing in the match."