Police are planning to step up security amid fears that the spat between Carlos Tevez and Gary Neville would linger into Wednesday's Carling Cup semi-final second leg between Manchester United and Manchester City.
The first leg, which City won 2-1, saw Tevez and United substitute Neville exchange gestures and later Tevez called his former team-mate "a moron" and "a bootlicker".
Tevez's agent Kia Joorabchian admitted the frosty relations between the two, sparked when Neville insisted United manager Sir Alex Ferguson was right not to keep Tevez at Old Trafford, could spill over into Wednesday's encounter.
Joorabchian, speaking on BBC Radio 5 Live's Sportsweek programme, said: "Carlos played two years at Manchester United and he has very good relationships with a lot of the players. He admires and likes Wayne Rooney and Patrice Evra and Ryan Giggs and he considers a lot of them friends of his.
"I don't think he will expect to have any atmosphere in relation to the players. But I guess he and Gary Neville are not going to be very good friends any time shortly."
Police made 18 arrests at last week's match and expect to make more before Wednesday's return after viewing video cameras.
And Ian Hopkins, assistant chief constable of Greater Manchester police, revealed talks would take place tomorrow with United and City officials and the Football Association in a bid to prevent any trouble.
Hopkins admitted he would also be reminding the players they had a responsibility not to provoke trouble.
He told Sportsweek: "I will be meeting with both the clubs again along with the FA tomorrow to discuss the general crowd behaviour and making sure that they understand their responsibility not to do anything that's likely to incite the crowd.
"We will be making the points very strongly that the players are professionals, they need to recognise the impact they can have on the crowd and it's going to be really passionate again on Wednesday. There's a lot at stake for both teams and for the fans."
Joorabchian, meanwhile, insisted that Tevez is not bitter at leaving Manchester United and his dispute is with Neville alone.
Joorabchian said: "If you don't have respect and class you have to accept that they are entitled to say something back. Gary Neville stepped into something that maybe he shouldn't have done and since he didn't have that respect Carlos felt he he had to answer.
"I don't think he (Tevez) has ever been bitter to Manchester United. I don't think Carlos came anywhere near hitting his peak at Manchester United. In the next three or four years he has a lot more to offer."
The player's advisor also believes the spat with Neville has only increased the anticipation around the match
He said: "When I went to the City match I saw an atmosphere which was absolutely unbelievable, a great vibe, so much passion in it. This little bitter matter has done nothing but improve this passion and it will give us an even greater build-up and a greater excitement."