Manchester United's trip to Chelsea tonight represents another opportunity for the English champions to prove that they still deserve to be considered among the Premier League's leading lights. With six defeats to their name already this season and leaders Arsenal 11 points above them, United's title defence seems all but over and they face a battle just to secure Champions League qualification. David Moyes' men trailed fourth-place Liverpool by five points ahead of the weekend and another setback at Stamford Bridge would further compromise their chances of fulfilling the minimum requirement of a top-four finish. We don't play a team that is 11 points behind the leaders. We play the champions, we play against Manchester United Jose Mourinho Their form against supposed title rivals does not augur well, as they have amassed only five points from a possible 21 in the seven games that they have played against the six teams above them in the table. Injuries to strike pair Wayne Rooney and Robin van Persie have made matters worse, but for all United's misfortune, Chelsea manager Jose Mourinho says it is too soon to write them off. "We don't play a team that is 11 points behind the leaders. We play the champions, we play against Manchester United," Mourinho said. "This is the way I feel. I've been too long in the game, I've played dozens and dozens of derbies and classic matches. This is what experience says. "On many occasions the team that looks to be in the most difficult situation is the team that appears stronger in that match. That's why I view this game as especially dangerous. I've not written United off." United can at least draw solace from a run of five wins in six league games, but Chelsea's recent form has been even more impressive. They have climbed to third place in the table, nine points above United, by winning eight of their past 10 matches and will be bidding for a fifth consecutive victory tonight. The teams played out a terse 0-0 at Old Trafford when they last met in August, but Moyes says it is hard to draw conclusions from that encounter. "That was a difficult game for both of us that probably came a bit too early in the season," said the United manager. "We know this is going to be hard because Chelsea are very strong at home. As you would expect, they have made a strong start to the season. "We are a little bit disappointed at not being in closer contention with the teams at the top, but we are hoping that between now and the end of the season we can do that. "We want to hang in there and if we could win this game it would make people think we are not that far away." Victory for United would certainly transform perceptions of Moyes' side - Mourinho has never lost a home league game with Chelsea and Moyes has never come out on top against the Portuguese. In the absence of Rooney and Van Persie, United will again turn to Danny Welbeck, who has scored six goals in his past six games, to lead the line. Chelsea hope that Frank Lampard will recover from a calf injury in time for tomorrow's game but right-back Branislav Ivanovic only returned to training on Friday following a knee problem and is unlikely to feature. Serbian midfielder Nemanja Matic could make his second Chelsea debut, having returned to the club from Benfica last week, but Mourinho has already confirmed that he will not start the game. "I'm in training, I played [for Benfica] on Sunday against Porto, so I don't have any problems," said the 25-year-old.