The Daily Mail says with City struggling to impose themselves on the Premier League, Kompany took Mancini to one side after training and offered some suggestions.
"Mancini didn't like that," revealed a source. "He thought Kompany was getting too carried away with his own importance. He told him so, too. Their relationship never recovered."
With Kompany - one of the dressing room's key figures - harbouring increasing misgivings about Mancini this season, perhaps it is no surprise the City coach did not survive.