Ten-man Arsenal missed the chance to go top of the Premier League as Diego Costa’s winner gave Chelsea victory at the Emirates Stadium.
The Gunners never fully recovered from defender Per Mertesacker’s 18th-minute red card, awarded by referee Mark Clattenburg after he hauled down Costa as the striker raced clear.
The revitalised Costa scored the decisive goal five minutes later, turning in Branislav Ivanovic’s cross at the near post to make it nine Premier League games without defeat for Chelsea against Arsenal.
Arsenal’s potency suffered after manager Arsene Wenger decided to replace striker Olivier Giroud and introduce defender Gabriel to compensate for Mertesacker’s dismissal.
Victory would have put Arsenal back on top but Chelsea survived in relative comfort to leave the Gunners in third place with Leicester City now holding a three-point lead over Manchester City at the Premier League summit.