Adam Lallana struck a post and Dele Alli saw a point-blank shot blocked by Germany keeper Marc-Andre ter Stegen in the first half as England were superior for spells.
But Lukas Podolski's spectacular second-half strike was enough to earn Germany victory.
And Cahill admits the defeat will be a learning curve for his side.
Gary Cahill claims England's defeat to Germany will be a learning curve
"I thought we played well today, especially the first half, we controlled the game,” Cahill told ITV Sport.
"We just focused on the job we had to do, work hard and produce a performance we had to.
"We have gone in on that formation on the back of one day on the training pitch. It's difficult to grasp it straight away.
England player ratings against Germany
Wed, March 22, 2017
Express Sport brings you England's player ratings from their defeat to Germany
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Joe Hart – 6
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“We had the better chances in the game.
“I think when we look back and reflect, if we'd taken our chances we'd have won the game.
“It's a learning curve for us."