Manuel Pellegrini, the new Manchester City manager, needed the intervention of stewards and security officials after missiles were thrown at him before Manchester United's game against Chelsea.
Pellegrini was at the match to compile a report on United in preparation for the first Manchester derby of the season, on 22 September at the Etihad Stadium, but had to take shelter after being recognised when he got out of his car.
The incident was dealt with quickly and Pellegrini has told City he does not want to take it any further. He also stated he was happy with the way the Old Trafford stewards looked after him.
City, meanwhile, are set to complete the signing of Martin Demichelis after agreeing to pay Atlético Madrid €5m (£4.3m) for the Argentinian defender.