The 18-year-old Chelsea midfielder shone against the European champions midweek with the Blues winning 2-0 at Stamford Bridge to advance to the quarter-finals of the FA Cup.
And Keane, watching the match at home, was stunned by his quality at such a young age.
The Irishman said on Sky Sports: “He was fantastic, I was sitting at home having a cup of tea and some chocolate and I didn’t have the volume on, as the game started I literally got out of my seat and said, ‘who is this kid in midfield?’
“There are certain traits you want from a midfielder, obviously quality on the ball, football intelligence, composure, he had everything.
“It was one of the best performances I’ve seen in a long, long time. The downside for the kid is he has got to back it up, he’s started so well.
“His general play [got me out of my seat], the way he started, he was like a world class player, that’s what he looked like, straight away. I thought it was one of their experienced lads.
“I kept a close eye on him for the rest of the game, everything he done throughout the game had quality written all over it.
“Obviously he looks like a small kid, but big composure about him.”
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