John Terry's week went from bad to worse this lunchtime as his slip gifted Arsenal all three points at Stamford Bridge.
The Chelsea skipper, who also got his name on the scoresheet, lost his balance with five minutes remaining, allowing his Arsenal counterpart Robin van Persie to race through and put his side into the lead.
The home side started the all-London encounter brightly and could have taken the lead as early as the second minute. However, Daniel Sturridge's square-pass was intercepted by Gunners goalkeeper Wojciech Szczesny as Fernando Torres waited for a tap-in.
Chelsea did not have to wait long to break deadlock however, with Frank Lampard getting on the end of Juan Mata's cross to head his side into the lead in the 14th minute.
Gervinho then missed a gilt-edged chance to draw his side level, but the Ivorian was more accurate nine minutes before the break. After wriggling free of the Chelsea rearguard, he found Van Persie in space and the striker rolled the ball into an empty net.
Skipper Terry would be the Chelsea hero heading into the break however, beating Per Mertesacker to Lampard's corner kick and squeezing the ball inside the near post.
Arsene Wenger's side started the second half positively and after Aaron Ramsey lifted the ball over Cech's bar, the Welshman found full-back Andre Santos in space on the left and the Brazilian drilled his effort underneath Cech.
If Cech was unlucky with that goal, he was certainly at fault for the 55th minute strike from Theo Walcott that put Arsenal in the lead. The England international beat two defenders before shooting inside Cech's near post.
Chelsea fought back, however, and Mata turned scorer, curling an effort over Szczesny from 25 yards out with ten minutes remaining.
However, with the Blues pushing for a winning goal, the man at the centre of race row with Anton Ferdinand fell onto the turf and Van Persie took full advantage.
The Dutchman was not done there, rounding of his hattrick in stoppage as the Gunners launched a quick counter-attack.
The victory was Arsene Wenger's 500th in charge of Arsenal.
