If it was good enough for Lleyton Hewitt, it's good enough for Holger Rune, who hopes to become a Grand Slam champion by possessing lethal groundstrokes, an intense competitive spirit -- and a back-to-front baseball cap.

It may not be the height of sartorial elegance, but 20-year-old Rune will not be swayed by subjective questions of taste when it comes to what he wears on his head.

"When I played my second ATP in Santiago, I had some things in the hair. I didn't really like the style myself," said the Dane after making the second round at Wimbledon.

"After that I found it comfortable and nice to wear something. I thought I looked cool with the backwards hat. 

"I enjoy to have something on my head. I tried to play without, but then I sweat a lot, so it gets in my eyes."

Hewitt, the 2002 Wimbledon champion, was as combative on court as Rune is now, two decades on.

When the Australian clinched the 2001 US Open, he did so with his cap resolutely flipped backwards.

It was a style he had cultivated in his early teens.

When fellow Australian Darren Cahill came across a 12-year-old Hewitt, he asked the youngster to explain why he opted for that particular look.

"He said 'I just like it backwards'. And I said 'Aren't you supposed to wear the peak of the hat to protect your nose and eyes and keep your eyes out of the sun?'," Cahill recalled to the New York Times in 2018.

"And he said 'No, I just like it backwards'."

In an online poll by MensTennisForums.com in 2018, 36 percent of respondents voted Hewitt as the "Best player with a backward baseball cap" followed by Germany's Tommy Haas, with just under 33 percent.

"What the hell is Denis Shapovalov doing in this poll?" thundered one respondent.

- 'Just bored I guess' -

Three years later, the question was irrelevant when the Canadian ditched the hat for a headband.

"The hair always gets in my face. I wanted to cut my hair a bit shorter and just try out the bandana look," said Shapovalov.

"I definitely like it. I feel like it's different. I wore a bandana when I was really young, so it's kind of cool to just change it up. I was just bored, I guess."

However, at the French Open last month, Shapovalov had reverted to the trusty backwards cap.

John Isner is better known at Wimbledon for taking part in the sport's longest-ever match in 2010.

However, last year, his decision to wear his cap back to front against Andy Murray sent social media into meltdown, with critics suggesting it was not a good look for a man of 37.

"Isner should lose this match, by default. Purely for having a baseball cap on backwards," wrote one.

"I have absolutely no idea who this Isner chap is, probably quite a lovely guy, but seriously, wear your baseball cap like a grown-up or don't wear one at all!"

Russia's Karen Khachanov, another back-to-fronter, had to change his cap in a 2021 Wimbledon clash against Shapovalov.

The umpire detected that the underside of the cap's peak was too dark, contravening the tournament's all-white clothing policy.

- 'Rules are rules' -

"I think there was a little bit of black colour inside the hat. I don't know if you can really see it from inside," said a weary Khachanov.

"But rules are rules, so I changed it."

Baseball star Ken Griffey Junior is credited with being the pioneer of the fashion in the 90s.

Griffey said he picked up the habit as a child when he would wear his father's hats. They would often slip off so his solution would be to wear them back to front.

Rune hopes the focus at Wimbledon will switch to his tennis rather than what he chooses to pop on his head.

"Maybe the next thing will be a banana," he joked.

dj/jw