Manchester City midfielder Nigel de Jong has warned controversial team-mate Mario Balotelli to stop acting like a "fool". Balotelli has repeatedly earned headlines for his bizarre antics on and off the pitch since moving to Eastlands from Inter Milan and the City striker was at it again over the last week. First the Italian irked City boss Roberto Mancini by using his time off to make an unscheduled appearance at the press confererence to unveil new Inter boss Andrea Stramaccioni. Then Balotelli, who also set fire to his bathroom by letting off fireworks earlier this season, was involved in a dressing room bust-up with Yaya Toure over the taking of a second-half free-kick in last Saturday's 3-3 draw with Sunderland. Balotelli's latest antics have come at a bad time as City have surrendered top spot in the Premier League to Manchester United and are now five points behind their arch rivals. With the title slipping away, Dutch star De Jong has urged Balotelli to stop courting controversy and concentrate on helping the team get back on track. "Sometimes Mario is a fool and at other times he is a genius - there are two sides to him, " he told The Sun. "Lots of people expect him to pull off crazy stunts and as a result he feels he must do something. People like that need to have upheaval in their lives in order to perform. "He is happy in his personal relationship. That is important and it makes him more focused. But he knows that he has to become more serious-minded."