Yaya Toure scored a hat-trick including two penalties as City wrapped up a punishing 5-0 win over bottom club Fulham and Luis Suarez's prolific run continued with three goals as Liverpool twice came from behind to thrash Cardiff City 6-3.
The goals were spread about for Chelsea as Samuel Eto'o, Andre Schuerrle, Eden Hazard, Oscar (2) and Mohamed Salah were on target for the leaders in a match likely to be remembered for a bizarre refereeing blunder as much as Chelsea's cut and thrust.
Official Andre Marriner flashed a red card at Arsenal's Kieran Gibbs for a handball on the goalline by Alex Oxlade-Chamberlain.
The sending-off did little to affect the destination of the points, however, as Arsenal were already 2-0 down when Gibbs was dismissed and Hazard stepped up to convert the resulting penalty to make it 3-0 after just 17 minutes.
Chelsea stayed four points clear of Liverpool in second, the Londoners having played a game more, with Manchester City six adrift of Chelsea in third but with three games in hand. Arsenal slipped to fourth.
Everton moved up to fifth with a 3-2 win over struggling Swansea City and Norwich City improved their chances of avoiding the drop by beating relegation rivals Sunderland 2-0, their second a stunning volley from Alex Tettey.
West Bromwich Albion lost 2-0 at Hull City and Newcastle United's Papiss Cisse scored in stoppage time to inflict a painful 1-0 defeat on Crystal Palace.
Image: Chelsea players celebrate after Eden Hazard scored the fourth goal against Arsenal.
Photograph: Richard Heathcote/Getty Images
Real Madrid v Barcelona: The ' El Clasico' in numbers
PHOTOS: Chelsea rout Arsenal as referee sends off wrong player
Survivor Wenger still doing it his way
'Arsenal squad want Wenger to sign new contract'
What you must not miss in the EPL this weekend