The Blues utilised a wing-back system for the majority of last season.
And, following their success, Arsenal adopted the same set-up towards the end of the campaign.
The Gunners’ results picked up and Carragher reckons it was a game changer for Arsene Wenger.
“There hasn’t been too much change to that starting XI,” Carragher said on Sky Sports.
“There are a lot of players at Arsenal, there’s more talk of players going out than coming in.
“The one big change really, rather than personnel, is system.
“Since Arsenal changed to that back three, maybe on the back of Chelsea’s success, it completely changed the season really.
“You think of the big semi-final win against Man City, winning the cup final, also winning the Community Shield. So can that be the change?
“Instead of players coming in and what he’s spent, there’s a different way of playing, that’s bringing the best out of the players already at the club.”
Arsenal started three at the back in their 4-3 win against Leicester last night.
But with Per Mertesacker Laurent Koscielny and Shkodran Mustafi missing, Arsenal struggled defensively.
