The FA have asked Manchester United and Chelsea to file a full report on the post-match flare-up that took place at Stamford Bridge on Saturday.

Sir Alex Ferguson, the United manager, says he is "very happy" to honour the FA's request, which comes after two days of claim and counter claim on what sparked the row. Both clubs have put forward differing versions of the events that led up to a 30-man melee, which saw United's players clash with Chelsea groundstaff, but they have now been asked to give their side of the story.

The FA have launched a full investigation into the incident and are thought to be examining CCTV footage as they attempt to uncover what sparked the row, although Ferguson seemed more than happy for their inquiries to proceed.

He said: "We are filing a report which will be sent to the FA. We are very happy with that, we are delighted with that. We hope the FA investigate it."

Carlos Tevez and Gerard Pique claim the row started when Patrice Evra, the Manchester United defender, was verbally abused by a member of the Chelsea groundstaff after ignoring a request to avoid warming down on a worn part of the pitch. Yet Evra’s representatives have denied that the defender was abused. The 27-year-old was due to give his account of the incident to Manchester United officials today.

Whatever was said, an altercation then took place between Evra and the Chelsea staff in which the men appeared to try to exchange punches. Chelsea are adamant that their staff behaved properly and were the wronged parties in both incidents and will help the FA with its inquiries.

Ferguson remains bullish about his side's chances of securing a Premier League and Champions League double, despite the setback at Stamford Bridge.

"We should be sitting here as champions of the league," he said. "I think decisions, bad decisions have gone against us. But it does not matter about those decisions now.

"When we signed on in August, it was to play 38 league matches and we need to win the last two to win the league. So be it. No matter what has happened, terrible performances or great performances, bad decisions, that's in the past.

"We have a semi-final tomorrow, then a home game on Saturday (against West Ham) and a game against Wigan away... disaster"

The United manager also defended his decision to leave Cristiano Ronaldo and Carlos Tevez on the bench at Stamford Bridge, with the Barcelona game looming.

He added: "Given we had played Barcelona on a Wednesday there was no way I could play the same team at Chelsea as it was a lunchtime kick-off.

"I have to give my team the best possible chance of getting to the Champions League final. This club should have had more success in Europe, so it was very easy for me to make those changes on Saturday."

In a seperate incident on Saturday, Rio Ferdinand, the United defender, was also forced to release a statement to explain why he kicked a female steward following the defeat. Ferdinand insists he was aiming his anger at a nearby wall but accidentally connected with the steward before kicking a door on his way to the dressing-room.