Roberto Mancini has warned Mario Balotelli of his conduct after the striker stormed down the tunnel following his substitution in the derby defeat at home on Sunday, the Daily Mail reports.

Manchester City suffered their first league defeat of the season at the hands of their bitter rivals Manchester United in a pulsating encounter which finished 3-2 at the Etihad.

The game was unfortunately marred by other incidents. A coin thrown from a City fan which left Manchester United's Rio Ferdinand pouring with blood from a cut above his left eye, while Balotelli also put himself in the spotlight for the wrong reasons as he stormed down the tunnel after being withdrawn early in the second half following a below par performance.

"I love Mario but it is important for him to start to think about his job," said Mancini.

"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."

The unpredictable Italian striker was surprisingly given the nod ahead of Carlos Tevez for Sundays key game, but it was only when he was eventually replaced by Tevez that City began to launch a comeback.

Balotelli after initially snubbing Mancini, did eventually return to watch the game from the bench only to see a late deflected Robin van Persie free kick seal a 3-2 victory for the Red Devils.