UEFA have confirmed they have received a protest from Lille about Ryan Giggs' controversial winner in Manchester United's 1-0 Champions League victory.
The French club have made a complaint about Giggs' quickly-taken free-kick, claiming a violation of the laws of the game by the referee Eric Braamhaar, which led to the home side appearing to contemplate leaving the field.
A decision will be taken on Friday afternoon.
The European governing body had already announced they will investigate the incidents which marred the first leg of the last-16 tie in Lens when French police were criticised by fans for being heavy-handed at the Stade Felix-Bollaert, and tear gas was used during the match.
The investigation into the safety concerns in Lens will also look at possible ticketing problems which led to supporters appearing to be in danger of being crushed against a 10-foot high safety barrier.
A statement from Europe's governing body read: 'UEFA has officially opened an investigation into events at the UEFA Champions League first knockout round first-leg match between Lille and Manchester United in Lens on Tuesday night.'
UEFA's control and disciplinary body will discuss the safety and security issues on March 22, more than two weeks after the second leg of the last 16 tie.
The date effectively rules out the expulsion of the French side from the tournament in the way Feyenoord were kicked out of the UEFA Cup this season for crowd disturbances.
United lead the tie 1-0 following Giggs' free-kick which almost led to Lille players walking off the pitch in protest.
Lille president Michel Seydoux vowed after the game to contact UEFA president Michel Platini and is expected to lodge an official protest.
UEFA officials are set to discuss the behaviour of the French side on Friday.
'If Lille had done the same thing the referee would not have allowed the goal,' said Seydoux.
While Giggs' controversial goal came seven minutes from full-time, there was growing concern over safety in and around the stadium before the Wales winger struck.
A supply of counterfeit tickets has been blamed for the situation developing but French police have also been accused of overreacting.
United officials are still looking for fans to come forward with information and and they are liaising with police, Lille, UEFA and security officials.
Gary Neville was also hit by a missile thrown from the crowd in the match played in Lens as Lille's Metropole Stadium does not meet UEFA standards.
Sports Minister Richard Caborn believes UEFA should address the problem of teams not having the required standard of stadia.
He said: 'The incidents were totally unacceptable, I will be looking to raise the issue of safety at major sporting events with my European counterparts at the council of sports ministers in Germany in March.
'I will also be examining the UEFA report on events in Lens and asking them what measures they are taking to ensure all grounds across Europe adhere to their minimum safety standards.'
Fans have arrived back in England complaining about police using batons. With supporters carried onto the pitch, the fears of a crush had echoes of the Hillsborough disaster involving Liverpool fans in 1989.