Manchester United manager Sir Alex Ferguson and striker Wayne Rooney face a Football Association investigation into allegations that they confronted referee Steve Bennett at the interval of their team's 3-1 derby defeat away to Manchester City here Saturday.
The pair are alleged to have hurled expletive-ridden outbursts at Bennett in the tunnel at the Eastlands Stadium after United took a 2-0 deficit into the break.
Rooney is also said to have caused damage to United's dressing room door as he swore and hurled abuse at the referee in front of numerous eye witnesses.
United was infuriated at City's first goal by Trevor Sinclair which it claimed was offside, and with a booking Rooney received for dissent just before the halftime whistle.
Matters worsened in the second half as Cristiano Ronaldo was shown a straight red card for a lunge at Andy Cole and, if Bennett reports the United pair in his post-match paperwork, worse could follow with FA disciplinary sanctions a possibility.
Bennett was not originally scheduled to officiate in the match but took charge after fellow referee Mark Halsey pulled out earlier in the week through injury.
The loss left United 13 points behind leader Chelsea, ahead of the reigning champion's trip to bottom-of-the-table Sunderland yesterday. United's defeat was compounded by Liverpool's 1-0 win against Tottenham that saw it move to within a point of United with two games in hand, ahead of the European champion's trip to Old Trafford next week.
Ferguson had to substitute Patrice Evra at halftime, after the defender - who joined United in a 5.5 million- pound move from Monaco earlier this week - endured a nightmare debut.
Two goals in the space of eight minutes toward the end of the first half from Trevor Sinclair and Darius Vassell put City on top before Ruud van Nistelrooy managed to pull one back for United 14 minutes from time.
However, substitute Robbie Fowler sealed City's victory with a stoppage-time strike.