Robin van Persie is facing the possibility of a Football Association charge after he was accused of elbowing the Newcastle midfielder Yohan Cabaye in the face.
The Newcastle manager Alan Pardew has called for action to be taken after Cabaye was left holding his face in the 84th minute after the pair clashed off the ball.
"He's looked at Yohan and he's elbowed him," said Pardew. "That needs to be looked at. There was a bit of history last year [when Newcastle lost at Arsenal]. I don't know if Robin's got caught up in that. There was a bit of unsavouriness in the game. I actually thought Yohan wouldn't have gone down if he hadn't done something.
"I didn't see it myself but I have looked at it on the replay and it looks like he's looked at him and then put his elbow there. That is for them to look at [the FA], not me."
Match referee Howard Webb did not appear to see the incident on the edge of the hosts' penalty area. Newcastle lost to Arsenal through an injury-time goal at the Emirates back in March, when Van Persie had to be dragged apart from fellow Dutchman Tim Krul after the game had finished. On this occasion, there were words exchanged between Cabaye and Van Persie before the French international went down holding his face. The FA will review the situation after they have received the report from Webb, who appeared to tell a complaining Cabaye that he had not seen the coming together.
If Webb reviews the incident and decides he would have sent Van Persie off if he had seen it, the FA will take retrospective action and he could face a three-game ban for violent conduct. Sir Alex Ferguson was not asked about the incident in his immediate post-match television interview.
Ferguson did claim that the victory, which moved his side up to second in the Premier League table, was a sign his team had returned to their best. Jonny Evans and Patrice Evra scored from two corners from Van Persie and Wayne Rooney inside the first 16 minutes before Tom Cleverley curled in a late third.
"For the whole game we were on the top of our game," Ferguson said. "There was concentration and determination, everything you want to see in a team that's going to win.
"Concentration is so important, the concentration and how we played in the first 20 minutes, it's strange because for all of the good football we played we scored from two set-pieces. We'll take it anyway.
"Wayne Rooney is getting fitter all the time, with about 20 minutes to go I could see signs he was tiring a little bit, he'd put so much work into it so I took him off. Some of his football was terrific.
"He likes to work a bit more forward, but we set up the diamond with him in the middle of the pitch. It gives different options for us. We played well on Tuesday night with that diamond and I wanted to see how far we could go with it."
Rooney added: "It is a huge result. This is probably one of the hardest games of the season. We came here, defended brilliantly and scored three goals so overall we fully deserved the victory.
"Our focus was the key. Certainly the first six games of the season, we haven't defended well enough. That isn't just the back four, that's the whole team. Today we were brilliant. They're a big team, a physical team and we knew we had to defend our box really well. We managed to do that and score three goals. There was a focus about us and we need to continue to do that for the rest of the season if we are going to be successful.
"I enjoy that position because I'm involved the whole game. I'm not at all anxious [about not having scored this season], we've got players who can score goals for us other than myself. If it comes, it comes."
Newcastle did have an appeal for a goal after a Demba Ba header in the 50th minute that David de Gea clawed back from behind the line. Replays were inconclusive whether the whole ball had crossed, but Ferguson added: "I thought the evidence was inconclusive to be honest with you, the whole ball has got to be over, but I would have been disappointed if we had not been given a goal in that situation. The goalkeeper has done fantastic to get there, but I thought enough of the ball was over."