The former Gunners centre-back was promoted to assistant manager over the summer following the departure of long-standing coach Pat Rice and has seen the side concede just four goals in seven games.
"Pat Rice was great, but because of the way Steve played the game, it's just a massive positive for us," Djourou told The Mirror.
"Steve works on team shape. With Arsenal, people have always blamed the defence for our problems, which I have always felt has been pretty harsh.
"Now it is the whole team that defends. There is a massive difference now to what we had before."
Arsenal will be looking to maintain their unbeaten run in the Premier League this weekend when they host London rivals Chelsea on Saturday.