Wayne Rooney's double helped Manchester United down Liverpool 2-1 here Saturday as the ill-feeling remaining from the Luis Suarez racism controversy escalated.
Suarez scored an 80th minute consolation for Liverpool to ensure an anxious finale for United but the game will be remembered for other reasons involving the Uruguay international.
Players from both sides had to be separated in the tunnel at half-time by police and stewards as Patrice Evra confronted Suarez, starting a game for the first time since serving an eight-match FA suspension handed out for making racist comments to the United defender.
There were also ugly scenes on the final whistle as Evra celebrated with United supporters and infuriated Liverpool players with his gestures.
Again, stewards, police and match officials were involved in keeping rival players apart.
Suarez had refused to shake Evra's hand before the game and the animosity between the pair further incited what has long been one of the most bitter rivalries in British football.
However chaotic the scenes at half-time, United clearly responded superbly after the restart, Rooney scoring twice in the opening five minutes of the second half.
After just over a minute of the period, Ryan Giggs' right-wing corner was helped on by Liverpool's Jordan Henderson and Rooney was unmarked to volley the ball home from half a dozen yards.
Then, three minutes later, Jay Spearing was caught in possession by Antonio Valencia who advanced purposefully before sliding the ball through for Rooney to finish clinically from 12 yards.
Both managers had called for calm in the pre-game build-up and spoken of the need to move on but Suarez's snub of Evra as the teams lined up before kick-off ensured the bitter dispute rumbled on.
When the attention finally switched to the football, Liverpool full-back Glen Johnson cut in from the right promisingly and fired in a near-post shot which David de Gea handled well although United soon responded with Danny Welbeck's neat touch finding Antonio Valencia whose far-post cross was well handled by Pepe Reina as Rooney prepared to pounce.
Jose Enrique tripped Valencia inches outside the box and Giggs' superb cross was headed behind well by Johnson with Rooney heading the resulting corner tamely at the Liverpool goalkeeper.
And Liverpool offered their hosts a reminder of how dangerous they could be on the break when a brilliant pass from Suarez set up Johnson for a fierce shot which bounced narrowly wide.
United were quickly back in the ascendancy and good work from Valencia played in Rafael whose curling shot was stopped by Reina before Rooney chanced his arm from the edge of the area and then, on 30 minutes, United came closest yet to an opening goal.
Veterans Giggs and Paul Scholes linked with the winger's cross finding the midfielder whose firm header brought a superb reflex save out of Reina from six yards.
United were forced into some committed defending before the end of the half, however, as Steven Gerrard and Martin Skrtel threatened with shots and Suarez broke through in the dying seconds with Ferdinand tackling him from behind.
Suarez appealed that he had been fouled and his frustration was evident on the half-time whistle when he kicked the ball violently into the crowd, team-mates Daniel Agger and Skrtel, either side of him, rushing to escort him from the field as tempers frayed further.
The incidents in the dressing room area made way for United's explosive start to the second half and, shortly after his goals, Rooney squandered the chance of a hat-trick when he mis-hit his shot after Scholes pass.
Giggs, following clever play from Welbeck, burst into the Liverpool area and saw a menacing far-post cross cleared as United sought the third goal that would kill off the game once and for all.
Suarez punished United for their wastefulness after 80 minutes, responding first after Ferdinand mis-controlled a deep Charlie Adam free-kick and firing into the goal from close range.
And, after Welbeck wasted an opportunity with a rash shot, Johnson almost claimed an improbable equaliser with a 20-yard shot which forced de Gea into an acrobatic tip over his cross-bar.