Arsenal thrashed Chelsea 5-0 at the Emirates last week, handing Mauricio Pochettino his biggest defeat as Blues boss. Former Chelsea player Kai Havertz scored twice and could not help but show his delight after his first goal. Havertz, of course, won Chelsea the Champions League back in 2021 after netting in the final against Manchester City, making him a club legend to some. However, the German had no problem with celebrating in Arsenal’s hammering of Chelsea after scoring the Gunners’ third goal in the London derby. Havertz’s reception was nothing like Mason Mount’s when he returned to Stamf…