Manchester United lost their lead in the title race and then lost the plot as tempers boiled over on a heated day at Stamford Bridge. Several of Sir Alex Ferguson’s players were involved in a scuffle with groundstaff and Rio Ferdinand accidentally kicked a female steward in separate flashpoints at the end of a controversial 2-1 defeat by Chelsea. United could face disrepute charges and Ferdinand may even lose his chance of becoming England captain, as Chelsea confirmed they are preparing to send CCTV footage of both incidents to the Football Association.

The extraordinary scenes followed an acrimonious second half in which United protested furiously about an 86th-minute penalty, converted by Michael Ballack for Chelsea’s winner, and Ferdinand was involved in a shoving match with John Obi Mikel and John Terry in Chelsea’s penalty box.

Still enraged, Ferdinand lashed out at a brick wall as he walked off the pitch and made inadvertent contact with a steward standing near by. Then, when United’s unused substitutes and non-playing squad members were warming down on the Stamford Bridge pitch, a confrontation with a Chelsea groundsman descended into apparent fisticuffs.

The players, Patrice Evra, Gerard Pique, Ji-Sung Park, Paul Scholes and Gary Neville, were asked to move to a different part of the pitch so groundstaff could water that area of grass. They refused and, after a verbal spat with Neville, the groundsman was allegedly struck by Evra and hauled away by colleagues as he attempted to retaliate. “We are studying relevant TV and closed-circuit footage and will be considering the appropriate course of action,” said a Chelsea spokesman. It is understood that film of both the Ferdinand and Evra incidents is likely to be on its way to Soho Square.

Ferdinand’s behaviour could cost him dear. The defender had emerged as favourite to be named as England’s new full-time captain by Fabio Capello when the qualifiers for the 2010 World Cup start in the autumn, but his actions may be considered unseemly by the FA at a time the governing body is pledging to improve players’ standards of behaviour. Capello was present at Stamford Bridge and witnessed several occasions when Ferdinand, and his England teammate Owen Hargreaves, lost their tempers with Alan Wiley, the referee.

It is not known whether Capello was still in the stadium when Ferdinand got into his pushing match with his rival for the England captaincy, Terry, though when the manager sees it replayed on television he is unlikely to be impressed.

Ferdinand moved to play down the incident involving the steward, and it is not thought the woman involved has made a complaint. In a statement released to the Press Association, Ferdinand said, “I kicked the wall in frustration at the result, as I have done in the past. Unfortunately a lady was standing by and I accidentally brushed her with my foot. I went back to make sure she was okay and apologised profusely. Credit to her, she laughed it off and was very understanding. She said she wasn’t hurt. I have arranged for a bouquet of flowers to be sent to her.”

Chelsea’s victory, which preserved their four-year unbeaten run in Premier League games at Stamford Bridge, allowed them to draw level with United on points at the top of the table, ensuring the title race will go down to the last day of the season on May 11.

United retain such a significant advantage in goal difference over their rivals that they will still be champions if they win their remaining games at home to West Ham on Saturday and away to Wigan on May 11. However, the impressive comeback by Chelsea, who were eight points behind United at one stage, means any further slip-ups may now be fatal to Ferguson’s team.

Avram Grant, the victorious Chelsea manager, claimed United may be cracking under the strain of trying to close out their 10th Premier League title. “It’s not easy when you are under pressure to win two games. We hope that we will be happy at the end of the season,” he said.

Carlos Queiroz, Ferguson’s assistant manager, ranted about Wiley’s refereeing. He was furious that Chelsea received a penalty, the first conceded by United in the Premier League this season, when Michael Carrick handled inside his box, while Ballack went unpunished for what Queiroz claimed was a push on Ronaldo.

“How can the referee not see that Ballack has jumped on Ronaldo? It must be necessary for a player to bring a gun and shoot one of our men in the box for us to get a penalty. There is something wrong with football,” Queiroz said.

Other moments of acrimony included a bizarre spat between teammates when Didier Drogba had to be restrained from confronting Ballack by Steve Clarke, Chelsea’s assistant manager, after an argument over who should take a free kick.

United’s headaches are worsened by injuries sustained by centre-back Nemanja Vidic and striker Wayne Rooney that could rule them out of Tuesday’s Champions League semi-final second leg against Barcelona at Old Trafford.

Rooney limped off the field with a sore hip, while Vidic had to be carried off on a stretcher after an accidental knee to the face from Drogba left him groggy.

“Vidic has a few stitches under his lip and he’s lost a tooth,” said Ferguson. “He was dazed rather than concussed but if we’d waited for him to come round we would have played 10 or 15 minutes with 10 men, and you can’t afford that in a big game, so we had to take him off.”