Sir Alex Ferguson has launched a stinging attack on Didier Drogba, claiming the Chelsea striker deliberately elbowed Nemanja Vidic during last weekend's Premiership title tussle at Old Trafford.
Vidic was forced to go for a scan on his jaw earlier this week as a result of the clash although, fortunately for the Serbian defender, there was no fracture.
However, he was still forced to sit out Wednesday's win over Everton to avoid suffering further damage.
Drogba was only booked by referee Howard Webb, when TV pictures showed the Ivory Coast star looking at Vidic before he leapt to head the ball, something Ferguson spotted as well.
'We could have lost a player for six weeks with a fractured jaw,' he said.
'Fortunately it wasn't, but it could have been.
'When I watched it again on video, I could see him (Drogba) looking round to see where he (Vidic) was. He could have done a lot of damage.'
Webb's decision to brandish a yellow card effectively prevented the Football Association from taking further action.
Although they made a special case when Ben Thatcher smashed Pedro Mendes in the face with his forearm earlier this season, Soho Square chiefs tend not to get involved when the referee has applied a punishment during a game, leaving Ferguson frustrated.
Last month, the United boss accused Chelsea of getting preferential treatment when it was confirmed referees' boss Keith Hackett would have a face-to-face meeting with Blues boss Jose Mourinho.
He also claimed Claude Makelele was lucky to escape dismissal for a tackle on Aston Villa's Juan Pablo Angel at Stamford Bridge earlier this season and believes Drogba has now become another Chelsea player to sidestep the law.
'Once the referee has given a yellow card, there is nothing you can do about it,' Ferguson said.
'Whether the rule should be changed is another issue but, at the moment, it is a FIFA mandate.
'There have been instances when the FA have taken action but, on this occasion, Chelsea have got off with it, again.'