Sir Alex Ferguson today stoked up his war of words with Chelsea by questioning why ground staff had decided to mow the grass at Stamford Bridge following Manchester United's defeat on Saturday.

FA disciplinary chiefs are set to monitor the incident on CCTV but the United boss appeared to suggest that the Blues were to blame for the incident because they should have cut the pitch before the match and not after the final whistle.

Ferguson confirmed that the champions will file a report to the FA on the post-match on-pitch brawl following their 2-1 defeat.

Several United stars, including Patrice Evra and Ji-Sung Park, clashed with ground staff after they had been asked to warm down on another part of the pitch which was being mowed in preparation for Wednesday's match with Liverpool.

He said: "We are filing a report and it will be sent to the FA, and we are very happy with that. We're hoping that the FA investigates it.

"But one question I want to ask - why were the lawnmowers on the pitch after the game to cut the grass? Aren't they supposed to cut it before the match?"

Premier League rules state that players from visiting teams are allowed to warm-down for 15 minutes after a game - they are just not allowed to use either goalmouth. Chelsea say footage shows Evra throwing the first punch, yet picture evidence clearly shows groundsman Sam Bethell with his first clenched in an aggressive manner.

United striker Carlos Tevez said: "During our post-match work, Evra received an insult from a Chelsea worker and my team-mates merely demanded an explanation. This was the problem and from that moment these men just wanted to attack Patrice.

"Obviously it's normal that we defend our team-mate, but within a few seconds all the United players were surrounded by stewards. I think the security cameras will show the provocation we received.

"I have never seen anything like this in my two years in England. We will happily give our version of what happened."

United, who face Barcelona in their Champions League semi-final second-leg at Old Trafford tomorrow night, must now win their last two League games to be certain of denying Chelsea the title.

But despite Saturday's incident-packed defeat, Ferguson insists that United are still on course to lift silverware this season.

He said: "Saturday's game has helped our preparations for the Barcelona game, no doubt about that. Having played at Barcelona on Wednesday night, there is no way that I could have fielded the same team at Chelsea, so I changed the team to give my players freshness and ensure they have the best possible chance of getting to the final.

"But I am not worried about the demands on my players. We should be sitting here as champions of the League now, but no matter of the decisions that have gone against us we signed up for a 38-game season and we have two games left to play.

"If we beat West Ham and Wigan in those games, we will be the champions. What a disaster!"

He may have to do without both Wayne Rooney and Nemanja Vidic who both missed training today. The United striker is struggling with a hip problem that forced him off the pitch on Saturday, while Vidic also had to leave the field after he was kicked in the face by Didier Drogba. Both were rated as extremely doubtful by Ferguson.