The five-time champions raced into a 4-0 lead at half-time and danced in celebration after every goal.
Manager Tite even got involved after Richarlison ran over to the dugout after scoring Brazil’s third goal.
But Keane could not understand the players’ antics and likened it to an episode of Strictly Come Dancing.
He said on ITV’s coverage of the match: “I can’t believe what I’m watching. Obviously brilliant, brilliant by Brazil.
“Fantastic finish by Vinicius, great start to the game. But I’ve never seen so much dancing. It’s like watching Strictly. I can’t believe what I’m watching.”
He added: “I don’t like this. People say it’s their culture. But I think that’s really disrespecting the opposition.
“It’s four goals, and they are doing it every time.
“I don’t mind so much the first jig, it’s the one after that, and the manager getting involved. I’m not happy about it. I don’t think it’s good at all.”
Fans found Keane’s comments hilarious with one saying: “Hahaha Roy Keane is in the mood!”
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Another added: “It’s like watching Strictly!” is a predictably great line from Roy Keane.”
And a third said: “Roy Keane is an absolute legend. How can he say I’m watching Strictly 😂.”