Central defender Cahill recognised Young's ability at England Under-21 level and then with Villa before he made the switch to Bolton three years ago.
But it is only now that Young looks completely at home for his country with his performances against Denmark, Wales and latterly Ghana at Wembley.
"You can see how much Ashley has developed even in the time from when I knew him at Villa," said Cahill. "He looks at home on this stage now but, when you've got that ability, you can play on any stage.
"He gets into little pockets of space and his awareness is outstanding. I thought he was brilliant against Wales and he had another good game against Ghana.
"His general awareness is good and he is such a threat."
Source: PA
Source: PA