No man, defensive player was not the main problem for chelsea. So far chelsea was controlling the game. The problem is when people didn't aware with the fact that if chelsea seems very hard to make a goal. I have seen that from so many matches if chelsea needs a good midfielder player. The current player doesn't seem to be a good choice anymore. There must be a new midfielder player that has capability to give assist to the attacker player.
The main problem that is always facing by chelsea in any game is midfielder was not able to send ball to the attacker