After going down two men and ultimately falling 2-0 at the hand of Chelsea, it's safe to say Arsenal keeper Petr Čech wishes he had played for his old side today. Before the match against his former club Chelsea, Čech appears to have tried to enter his old locker room—per habit? Or as a precaution for losing?The game was not without its controversy, as Chelsea striker Diego Costa pulled some dastardly moves to leave Arsenal short on numbers after being dealt a few cards. The Gunners would ultimately finish the game with only nine players.Regardless of the Costa antics, I'm sure it didn't feel good for Čech to have his former teammate Kurt Zouma head this set piece past him. Yeesh.Arsène Wenger will surely have Čech review his old playbook before the Gunners' and the Blues' next matchup.