The Aston Villa defender escaped punishment inside four minutes at the Tottenham Hotspur Stadium after elbowing the Spurs midfielder in the side of the head.
However the incident went unpunished, with Carlos avoiding a sending off for the offence, or even a booking.
VAR had been enduring technical issues in the early stages of the match, however the system was back up and running for the incident when it occured.
But while the elbow from Carlos didn't attract a big reaction during the first half, it was certainly pointed out in the Sky Sports studio at half-time.
Keane didn't mince his words, saying: "Silly boy!
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"He must look and think that he's obviously got no chance of getting the ball, but once you raise your elbow - a sort of swinging elbow - he's very, very lucky."
Ex-Tottenham defender, Michael Dawson was sat alongside Keane in the Sky Sports studio and added: "I can't believe it.
"As a defender you can sometimes use your arm, but he puts his elbow straight into Bryan Gil's face there.
"When it was live I didn't see anything.
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"The ball was so far away, you're thinking 'why is Diego Carlos getting involved in this' and you see the way Bryan Gil's face goes…he's a lucky, lucky boy."
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