Police have confirmed they are investigating the cause of an injury that hospitalised one of Chelsea's stewards after Sunday's match against Manchester United.

A Stamford Bridge steward needed approximately 10 minutes' treatment by paramedics after falling to the floor during the game, with the Blues confirming he had hurt his knee.

The injury was sustained as United celebrated Javier Hernandez's controversial winner in front of the Matthew Harding stand, home fans responding by hurling abuse and appearing to throw objects onto the field of play.

It was unclear whether the steward, who was taken to hospital, was hit but there were suggestions on Monday he may have been caught up in a surge towards the advertising hoardings.

The matter was serious enough for the Metropolitan Police to launch a formal inquiry.

A spokeswoman said: "We are aware of an incident during yesterday's match at Stamford Bridge in which a steward was injured.

"An investigation has been launched into the incident and our inquiries continue."