England played Germany last night using the 3-4-3 system Chelsea boss Antonio Conte has popularised in England.
Despite their 1-0 defeat to Germany, England were the better side for long periods of the game.
Cahill revealed there were lots of positives England can take from using the 3-4-3 system.
“We’ve gone into that formation today for the first time,” Cahill said.
“We had one day when everyone’s been out on the training pitch.
“It’s difficult to put in a new formation and have everyone grasp it straightaway.
“But there were a lot of positives from that.”