Manchester City manager Roberto Mancini has criticised Mario Balotelli following Sunday's derby defeat to Manchester United.
The controversial striker, who was selected ahead of Carlos Tevez, was taken off in the 52nd minute before he stormed off down the tunnel.
"I love Mario but it is important for him to start to think about his job," Mancini told Sky Sports News.
"He has everything to play well but he can't continue to play like today. We wanted more from him.
"When you have a player that has Mario's quality, you cannot understand why he continues to throw it out of the window. It is incredible."
Sunday's loss has seen United move six points clear of champions City in the Premier League table.