London:
Chelsea have a golden opportunity to cement their lead at the top of the Premier League by shattering Arsenal's title bid in Sunday's crucial London derby.
Carlo Ancelotti's side will move 11 points clear of the third placed Gunners with a victory at the Emirates Stadium and the Blues couldn't be facing their rivals at a better time.
Arsenal have been ravaged by injuries in recent weeks and Robin van Persie, Gael Clichy, Nicklas Bendtner, Kieran Gibbs and Abou Diaby will all miss this weekend's clash.
The injuries to Clichy and Gibbs mean third-choice left-back Armand Traore is likely to start, while even Arsene Wenger's available stars are ailing, with William Gallas and Andrey Arshavin sure to be pressed into action despite a nasty clash of heads against Standard Liege in midweek.
In contrast, Chelsea make the short trip across the English capital boosted by England midfielder Frank Lampard's return ahead of schedule after a thigh injury, while Michael Essien is expected to start after a knee problem.
With home victories over Liverpool and Manchester United already under their belts this season, the prospect of delivering a hammer blow to another of the 'big four' should provide Chelsea with all the motivation they need in north London.
Diplomacy dictates that, publicly at least, blues boss Ancelotti insists it will be too early to write off any of Chelsea's title rivals whatever the result on Sunday. But the Italian knows the message such a significant win would send to the rest of the league.
"When you play against a strong team like Arsenal or Manchester United, it's an important test. Arsenal are one of the most important teams in England and Europe," Ancelotti said.
"They're playing very well. I like their style, they try to play and attack to create difficulties for the other teams.
"It will be a very good test for us. We want to put the best on the pitch against Arsenal. I think it will be a fantastic match because both teams want to play football.
"Arsenal will want to win the game and Chelsea also, but it's not decisive for the title. It would be 11 points if we won, but Arsenal would have a game in hand."
Ancelotti, whose side go into the weekend five points ahead of United, will be encouraged by Arsenal's injury problems, but the former AC Milan coach prefers to focus on the form of his own team, who are unbeaten in eight matches in all competitions.
Key to his hopes of another memorable day in his brief reign will be the form of prolific forwards Didier Drogba and Nicolas Anelka, who was just 19 when he won the title with Arsenal in 1998.
Anelka, who scored the winner against Porto on Wednesday, has made a mockery of claims that he isn't compatible with Drogba and the Frenchman is desperate to end his long wait for a second English title.
"I was glad to win with Arsenal, we had a big team with big players and I hope I'll do it again," Anelka said. "Sometimes you have only one chance in your life and now there is a second chance to win it.
"Arsenal were strong but this Chelsea side are strong, too. I did it with Arsenal and I can definitely do it as well with Chelsea."
Chelsea's confidence is clear for all to see and Wenger did his best to counter that by talking up his team's readiness for such a crunch moment in their season.
Last weekend's defeat at Sunderland was Arsenal's first loss in seven league games, but that run was hardly against the most daunting opposition.
Wenger concedes that Arsenal cannot expect to be regarded as title contenders until they defeat a team like Chelsea.
"It is a big test, yesm but that is what you want, to play these teams," he said.
"I think there is a period for any team to come out and show its strengths. For my team, this moment has come.
"We are not any more a team that has to be considered to be young. I think we have the strengths and we can show that on Sunday that we are strong enough to compete."