Per Mertesacker was sent off after 18 minutes for a professional foul on Diego Costa and the Spaniard scored the only goal of the game minutes later to hand Arsene Wenger’s side their first home defeat since West ham in the opening day of the season.
The result means Arsenal remain third on the table, three points behind leaders Leicester City.
As for Chelsea this was by far their most impressive performance of the season, as they continue their climb away from the bottom of the table.