Romelu Lukaku is facing a three-match ban that would rule him out of the Manchester derby after he was caught on camera kicking Brighton defender Gaetan Bong in the groin.

Lukaku lashed out at Bong with his right boot, then connected with the Cameroon international with his left as they tangled at a corner moments before Manchester United’s goal at Old Trafford.

The 66th-minute incident went unnoticed as Ashley Young’s shot took a big deflection off Lewis Dunk and looped into the net, but it was captured on video and is set to land Lukaku in trouble on Monday.

Romelu Lukaku is looking at a three-match ban after being caught kicking Gaetan Bong

The pair went up for the ball, with Lukaku lashing out at the Brighton defender upon landing

As the ball fell out to Ashley Young on the edge, Lukaku swung his leg in the direction of Bong

Lukaku repeated the motion twice in quick succession while the ref's focus was on Young

The FA are aware of the incident and will study referee Neil Swarbrick’s report before viewing more footage.

United’s £75million striker faces a charge of violent conduct that carries an automatic three-match ban, potentially keeping him out of Tuesday’s game at Watford, Saturday’s trip to Arsenal and the Manchester derby at Old Trafford on December 10.

United desperately need to beat City to prevent them running away with the Premier League title, and losing their 12-goal top scorer would be a serious setback despite Lukaku’s recent loss of form.

Last month, Liverpool defender Dejan Lovren accused Lukaku of kicking him in the face during the goalless draw at Anfield. The FA took no action but are unlikely to be so lenient this time.

Despite starting the season well, Lukaku's purple patch has ended and he is now struggling

Should he be banned Lukaku will miss the crucial Manchester derby against rivals City

Jose Mourinho is likely to be furious should his star striker be ruled out of such a huge game

Although Jose Mourinho has talked about resting the Belgium international, who has played every minute of United’s Premier League and Champions League games this season, this is not the break he had in mind.

If Lukaku, who has scored just once in his past 10 games after claiming 11 goals in his first 10, is suspended, it will put pressure on the United boss to start Zlatan Ibrahimovic after three appearances off the bench following knee surgery.

Mourinho praised Lukaku’s commitment after he forced the corner that led to United’s winner by pursuing Brighton defender Solly March to the byline.

GRAHAM POLL'S VERDICT Manchester United striker Romelu Lukaku must face a three-match ban once the FA view replays of the incident between the Belgian and Brighton’s Gaetan Bong just before the only goal of the game. The incident started with the usual jostling between players at a corner but turned into a much more serious clash. Lukaku was impeded as the corner came in but his reaction was extreme, kicking out first with his right foot and then making full contact with his left foot somewhere quite painful. It was a violent act which would have resulted in a red card had referee Neil Swarbrick seen it. The Brighton full back did remarkably well to not react, nor complain to the officials. He deserves praise for that. Later in the second half, Swarbrick did see the challenge by Shane Duffy on Zlatan Ibrahimovic but failed to punish it correctly. Duffy flew into a tackle in the 87th minute with studs first and at pace, wiping out the Swede, who could have been seriously injured. It was also a red-card offence but, as Swarbrick punished it with a yellow card at the time, the FA cannot act. United manager Jose Mourinho will be understandably irritated if Lukaku is banned retrospectively after Duffy escaped, but he should take comfort in the three points because the only goal of the game — Ashley Young’s deflected effort — came just after the whistle should have blown for Lukaku’s assault. Poll: 'Lukaku reacted in the extreme and the FA should now take retrospective action' Advertisement

‘The way Romelu wins the corner for the goal, the way Romelu ends the game making tackles in the left-back position, that is the mentality I want,’ said the United boss. ‘Unfortunately, not every player is the same. So Romelu, for me, fantastic. He didn’t score. I don’t care.’

Brighton manager Chris Hughton was unhappy that assistant referee Marc Perry had pointed for the corner that led to the goal, even though replays appeared to show the ball taking the slightest touch off March on its way out of play. Goalkeeper Matt Ryan felt that Perry was not sure of his decision.

‘The reaction from the linesman himself, he was a little bit nervous, I felt,’ said Ryan. ‘He sort of gave a home field decision.

‘There are 50-50 decisions at the end of the day that perhaps go the home side’s way.’

The nature of the goal was harsh on Brighton, who comfortably soaked up United’s pressure and created arguably the better chances. United could not be faulted for effort.

What they lacked was finesse and the ability to break down Brighton, even though Mourinho once again started with Lukaku, Marcus Rashford, Anthony Martial and Juan Mata, then sent on Ibrahimovic and Henrikh Mkhitaryan.

SPORTSMAIL'S MARTIN KEOWN If Jose Mourinho wants to get Romelu Lukaku firing again, he needs his £75million striker to reach boiling point. I am not talking about a petulant reaction to a penalty-box wrestle with an opponent, but rather his performance. It might be the right moment to leave him out against Watford tomorrow. Lukaku has scored a single goal in his last 10 games in all competitions. Give him some space so that he comes back an angry man, with some fight and determination. I have described Lukaku as a pussycat, whereas Manchester United want a lion on display (and we all know which animal Zlatan Ibrahimovic likes to compare himself to). It is about how you get Lukaku to that stage. He was bought to lead the line and score the goals to win the title. That isn’t happening. Lukaku’s kick on Brighton’s Gaetan Bong — which was picked up by a television camera at Old Trafford but not by the referee — shows he is getting frustrated. That is not the right type of reaction. When Mourinho was at Chelsea the first time, he had untouchable players who were the first names on the team sheet. Lukaku could be one of those at United, but not in this form. He looks a bit lost. Keown: 'Mourinho should probably leave Lukaku out to provoke some determination' Advertisement

Dejan Lovren (L) accused Lukaku of kicking him in the face last month, but it wasn't followed up

SUPER STAT Brighton defender Lewis Dunk is the first player in the Premier League era to score an own goal versus both Manchester clubs in the same season. Advertisement

Perhaps the most positive thing you could say about United is that this was the kind of game they drew at home last season, and a point was the very least Brighton deserved.

‘Do I expect Man United to have more chances against us? Yes,’ said Hughton. ‘Probably you have to give us a bit of credit.’

Certainly, United lack the ability to open up teams in the way City have this season, a point raised awkwardly by Eric Cantona before this game and endorsed afterwards by Ryan.

‘City have been pretty prolific going forward,’ said the Brighton keeper. ‘They play an exciting brand and perhaps United play a more structural sort of game — more direct with a lot of big guys.

‘I don’t think they really outplayed us and cut our defence to pieces.’