Charlton Athletic 1 Arsenal 3
Having heard just before kick-off that Chelsea had won at Liverpool to move eight points ahead of them Arsenal knew that nothing less than three points would be good enough if they were to keep Jose Mourinho's team in their sights.
But Arsenal, without a number of key players, had a difficult first half and were fortunate to go in level at the break.
Charlton were full of confidence having been the Premiership's most successful team in December and Dennis Rommedahl brought a save from Manuel Almunia just 34 seconds in and Danny Murphy and Jonathan Fortune had half chances to put the home side in front.
It was against the run of play when Arsenal added their second shot on target and took the lead after 35 minutes.
Patrick Vieira broke into the Addicks penalty area and found Freddie Ljungberg seven yards out, who turned and rifled the ball into the net past the stranded Dean Kiely.
Charlton's deserved equaliser came with a sensational goal from 35 yards by Moroccan defender Talal El Karkouri after a free-kick had been tapped to him by Matt Holland.
The goal made the central defender Charlton's top scorer with just four goals. It was a blow for Arsenal right on the break, but nothing more than the home side deserved.
Arsenal took the initiative straight after the break when Ljungberg scored his second goal with a lovely shot from 20 yards that again left Kiely with no chance.
Thierry Henry had seen a free-kick headed off the line, before Dutch forward Robin Van Persie sealed the points for the visitors with an angled shot after he got behind a hesitant Charlton defence.
That goal knocked the stuffing out of the home side and Arsenal were able to coast home in the last 20 minutes, with Almunia enjoying a comfortable afternoon in the Gunners goal.
This was Arsene Wenger's side's fourth successive Premiership victory and the 31st match against other London top-flight sides unbeaten since they lost to Charlton 4-2 in November 2001.
This was only Charlton's third defeat in ten matches, the other two also being against top sides Chelsea and Manchester United.
Man of the Match: Freddie Ljungberg – The Swedish midfielder scored twice to help the Gunners stay on the coat-tails of Premiership leaders Chelsea and maintain his side's excellent record in London derbies.