Chelsea could go back to the top of the Premier League with victory against Birmingham providing Arsenal fail to match their result at seventh-placed Aston Villa, the first of a daunting series of fixtures for Arsene Wenger's side.
Both Arsenal and Chelsea have 48 points and an identical goal difference, such is the closeness of the race to snatch the league title away from leaders Manchester United who have 50 points but have played more games.
Strikers Didier Drogba and Salomon Kalou will not be available for Carlo Ancelotti's side despite the Ivory Coast's surprise defeat by Algeria in the African Nations Cup but Chelsea have done pretty well without them, scoring seven against Sunderland in their last league match.
Nicolas Anelka's form has made light of Drogba's absence.
"Nicolas is definitely as good as any centre forward in England at the moment," assistant manager Ray Wilkins said after Chelsea's 2-0 FA Cup win at Preston North End on Saturday.
"He's playing some of the best football of his career. Nico has always been a wonderful footballer but he's added more to his game."
Birmingham will present a severe test for Chelsea and will arrive full of confidence after a 2-1 FA Cup victory at Everton had fans singing "We are unbeatable."
"Belief has a powerful impact in a dressing room and these players should realise the power they've got now," manager Alex McLeish told The Times.
"Individually, you can have one or two mavericks in a team who can win you games, but they won't win you as many games as when you've got a dressing room as full of the power that I've got in mine."
Arsenal saw another chance of silverware vanish on Sunday when a below-strength side lost 3-1 to Stoke City in the FA Cup - a result that means Wenger's side can focus solely on the title chase and Champions League.
The north Londoners are unbeaten in the league since late November.
However, with Villa away, followed by United at home on Sunday, Chelsea away and Liverpool at home, the Gunners are entering a period which could make or break their season.
"It is important for us to focus on the next four games because we in an interesting position and of course on Wednesday night we have a very important game at Villa," Wenger, who drew some criticism from fans for picking a weakened side at Stoke, told Arsenal's website.
Wenger said defenders Bacary Sagna, Thomas Vermaelen and Gael Clichy would be available for the trip to Villa after they were rested at the weekend.
