By Arsenal correspondent Tony Hughes 

Olivier Giroud was furious at being sacrificed by Arsenal after Per Mertesacker’s red card against Chelsea.

Mertesacker was given a straight red for a professional foul on Diego Costa 17 minutes into the showdown at Emirates Stadium.

Referee Mark Clattenburg had no hesitation in dismissing Mertesacker, who was the last defender as Costa latched on to a precise pass from William.

Arsene Wenger reacted to the sending-off by bringing on Brazilian defender Gabriel to partner Laurent Koscielny in central defence.

Surprisingly, Wenger sacrificed Giroud, Arsenal’s leading scorer this season with 18 goals.

The Frenchman is said to have sustained a knock in training on Saturday but he made clear his disapproval at the manager’s decision by shaking his head as he trudged off the pitch.

Minutes later, Costa gave Chelsea the lead when he volleyed in Branislav Ivanovic’s right-wing cross at the near post.