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 racket strings and slams his knees to get the frustration out.

"All (people) have this situation in life and you just lose it," added the 13th-ranked Rublev, whose coach, Marat Safin, said he broke 1,055 rackets during his playing days.

"It doesn't have to be tennis. It's just the thing (in) tennis, you are alone and they are watching you," Rublev said.

"Some people face it better, some let those emotions kind of control you. I'm one of those guys who let those emotions take over me."

Medvedev, a fellow Russian, is the same way.

Medvedev smashed his racket on the red clay seven successive times midway through an unusually poor performance from the former No 1 player at the start of the claycourt season — a 6-0, 6-0 "double-bagel" defeat to Matteo Berrettini at the Monte Carlo Masters.

Medvedev finished off his angry display by depositing his mangled frame in a courtside trash bin.

"When I broke the racket, I kind of didn't (want to)," Medvedev said.

"Usually, I do want to do it when I do it. There, I didn't want to. But I was like, 'you know, it's 6-0, 6-0. I cannot win one point.'

"Maybe sometimes this can give you a boost. And it didn't."

Last week, German player Altmaier slammed his racket on the clay and then kicked the frame into the stands when his frustration boiled over during a tournament in Hamburg. He was fortunate that no spectators got injured because of his behavior.

Even the big guns lost it

Even Roger Federer was known for smashing his racket as a junior player.

Then he cleaned up his act and become one of the classiest — and most successful — players in tennis history.

At the 2009 US Open, Serena Williams was penalized for shouting and cursing at a line judge who called a foot fault.

In 2020, Novak Djokovic was kicked out of the US Open for accidentally hitting a line judge in the throat with a ball — resulting in a stunning end to his 29-match winning streak.

Top-ranked Aryna Sabalenka has also been known to lose her cool. Although she's improved in that department lately.

"My emotions were destroying my game and my level was dropping dramatically when I would start overreacting on everything," Sabalenka said.

"At the same time, my opponents would see that, and they would step in and play better."

Sabalenka said keeping her emotions in check has been "a huge improvement over the years in my career and really helped me to level up".

When Coco Gauff's off-court racket-smashing moment at the Australian Open was documented on camera, it opened up a debate about players' privacy.

Fifth-ranked Jessica Pegula also tends to keep her racket-smashing for off-court moments.

"I go find some place that's, like, maybe not near people and then I can break a racket," Pegula said.

On court, Pegula is able to keep her emotions in check.

"I'm not a super emotional person in general, so, I think, for me to like get to that point is a lot, but I think it's entertaining," Pegula said.

"Sometimes I wish I could kind of wear my heart on my sleeve a little bit more and show more emotion, but it's not exactly my persona."

Naomi curses quietly

Naomi Osaka is another player known for keeping a steady demeanor on court. It wasn't always that way, though.

"Honestly, I had a pretty bad attitude when I was younger and my dad had a stern talk to me about it," Osaka said.

Osaka now releases her anger so quietly that it's hardly noticeable.

"I actually do curse a lot on the court," Osaka said. "I say it so softly you can't hear it and I'm really glad, because I don't want to get fined for that."

Sorana Cirstea, the 36-year-old who this week became the oldest player to make her debut in the top 20, had a simple explanation for all the displays of emotion.

"It's such a mental sport. Also, to be able to sustain that mentality for three long hours with all the adrenaline and the pressure, sometimes you don't handle it (in) the best (way)," Cirstea said. "We are human."