Chelsea silence Arsenal

Diego Costa returned to haunt Arsenal once again as he scored the only goal in Chelsea's 1-0 victory at the Emirates having been involved in Per Mertesacker's sending-off.

Arsene Wenger's Premier League title hopefuls started brightly, but suffered a massive setback as Mertesacker was given his marching orders after 18 minutes.

Chelsea broke forward through Willian, and the Brazilian's weighted pass in behind Mertesacker led to the World Cup winner sliding in on Costa as last man to receive a red card from Mark Clattenburg.

Wenger responded to the dismissal by taking off in-form striker Olivier Giroud for Gabriel Paulista, much to the disappointment of the French forward and the Emirates crowd.

Costa found space in between three Arsenal defenders and finished a clinical volley at the near post following a whipped cross from Branislav Ivanovic, who was playing his first game since signing a new contract with the title holders.

Flamini had a great chance to level the scores in first-half injury time after running onto a lobbed pass from Mesut Ozil, but wasted the opportunity by volleying well over the bar.

Chelsea were denied a potential penalty as Cesc Fabregas was barged over in the Gunners' area by Laurent Koscielny after 59 minutes, and Wenger then brought Alexis Sanchez on to try and turn the game around. ESPN