Chelsea lead 10-man Arsenal 4-0 at the interval of their Premier League encounter at Stamford Bridge.
Samuel Eto'o had a half-chance inside three minutes following a through-ball from Andre Schurrle, but Arsenal goalkeeper Wojciech Szczesny was out to clear at the vital moment.
Olivier Giroud came close for the visitors moments later, but his low effort was saved by Petr Cech.
The Blues were ahead after five minutes, however, when Eto'o curled one into the bottom corner from just inside the box.
It was 2-0 less than two minutes later when Schurrle found some space outside the box before drilling his shot into the corner of the net.
It got worse for Arsenal after 15 minutes when Kieran Gibbs was dismissed for handling the ball inside the box, despite replays showing that Alex Oxlade-Chamberlain had made the contact with his hand. Eden Hazard stepped up to send the home side 3-0 ahead from the penalty spot.
Chelsea came close to their fourth after 30 minutes when David Luiz struck an effort from distance, but a smart save from Szczesny prevented the home side from extending their lead.
The hosts had their fourth in the latter stages of the half, however, when Oscar converted a Fernando Torres cross from close range.
Matt Law
