The wing-back made a first Champions League start in Arsenal's 3-0 win against AS Monaco.
Cahill told BBC Sport afterwards: "The manager obviously has a lot of faith in him to start him in a game like that with Kieran Tierney on the bench. He had other options and he chose to go with the young boy. It looks like he has a very bright future at 18-years-old.
"It's interesting to hear Bukayo Saka speak about him like he is 35 (himself) when he is only 23 still. He impresses me so much, Saka. The way he carries himself. The way he performs. Everything he does at 23-years-old is unreal.
"Going back to Myles Lewis-Skelly, what a terrific Champions League debut, 18 years of age, he's got a bright future."
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