New Delhi, May 27 -- The tennis season is heating up with the French Open underway. That means that racket-smashing moments can't be far off.

In a sport known for its mental challenges, it's part of the game to see top players lose their cool on court. In recent weeks, Daniil Medvedev and Daniel Altmaier have each had memorable, racket-mangling meltdowns on Europe's clay courts.

But it's nothing new, as anyone who remembers watching John McEnroe decades back can attest to.

So what goes on inside players' heads that results in temper tantrums before packed stadiums?

"It's not about tennis," said former top-five player Andrey Rublev, who is known for his on-court anger - he sometimes bloodies his hands and body when he punches his racke...