The ever outspoken and eccentric former star whipped out an acoustic guitar to "reveal in a nutshell my belief that there should be no warm-up in tennis".
McEnroe, who now works as a TV pundit and analyst, made the "suggestion - one that may not be popular at all" as part of his role as 'Commissioner of Tennis' for Eurosport during the French Open.
"Come on, we're just tennis players - we're not laying our lives on the line," he sang.
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"Don't we want to make the sport more exciting?" he questioned.
"We've got to start thinking outside of the box!"
Does McEnroe have a point when he says that pre-match warm-ups are a waste of time in professional tennis? After all, players do often come straight from the practice courts themselves for their matches. Post your views below...