Watford heaped more misery on former England manager Steve McClaren with a 2-1 win at Newcastle while Bournemouth managed their first ever Premier League home win in beating Sunderland 2-0 yesterday.
The acrimonious relationship between Chelsea manager Jose Mourinho and Gunners boss Arsene Wenger seeped through to both teams at Stamford Bridge in a tetchy London derby featuring even more flashpoints than usual.
Wenger was furious Mike Dean opted not to send off Diego Costa following a clash with Laurent Koscielny and the referee further infuriated the Frenchman when he dismissed Gabriel for kicking Costa and then showed Cazorla a red card in the second half.
"In every game Costa has aggravation and he gets away with it because of the weakness of the referee.
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"Gabriel should not have responded but the two sending offs for us and Costa staying on the pitch is a shame (shameful)."
Mourinho's response felt designed to provoke Wenger as he said: "I don't have a view on the sending off. Man of the match for sure was Diego Costa. He brought everything to the game."
A surly pre-match handshake between old rivals Wenger and Mourinho set the tone for a feisty clash.
Gunners defender Gabriel remonstrated with Costa and was booked for his complaints.
But the Brazilian couldn't keep his emotions under control and in first-half stoppage-time he aimed a sly kick at Costa right in front of the referee, who immediately brandished a red card.
Chelsea made their numerical advantage count in the 53rd minute when French defender Zouma was left unmarked to head in a Cesc Fabregas free-kick.
Cazorla was sent off in the 79th minute when the Spanish midfielder caught Fabregas with an ugly lunging tackle.