The Italy international was hauled off early in the second half after an ineffective display at The Etihad as Sir Alex Ferguson’s men ran out 3-2 winners after a thrilling derby.
Balotelli looked less-than-impressed with his manager’s decision to replace him with Carlos Tevez as he trudged straight down the tunnel in the 51st minute.
“I love Mario but I think it’s important for him to start thinking about his job,” said Mancini. “He can’t continue to play like today.
“When a player has this quality you can’t understand he will throw it out the window. This is incredible.
“There aren’t words I can say. It’s a bad feeling. When you lose a derby in the final second, it’s hard.”