"When Serena Williams won her French Opens, that was where she played her best tennis" - Chanda Rubin

Most of Serena Williams' famous Grand Slam victories have come either on hardcourts or on the lawns of Wimbledon. But the American has also won the Roland Garros trophy on three occasions.

According to former players and hosts of the weekly podcast 'The GOAT: Serena', Zina Garrison and Chanda Rubin, the red clay at the French Open in Paris is where Williams plays her absolute best tennis.

Recalling Serena Williams' Roland Garrios triumph on the latest episode of the podcast, the duo said they really enjoyed watching her adapt to the slow surface - where she wasn't the most comfortable.

"I think each time, for me, when [Serena] played well and won those French Opens, that was where she was just playing her best tennis," Rubin said.

"The red clay forces you to have to do everything, even things that you aren't as comfortable with or don't have to think about on the faster surfaces," she continued. "I was seeing Serena do that in each of those tournaments where she won in Paris."

Rubin added that red clay brought out every aspect of Williams' game, especially in some of the more difficult matches.

Willaims with the 2013 French Open trophy.

Garrison, meanwhile, highlighted Williams' familiarity with Paris - where she now trains during the off-season - as another major reason behind her success at Roland Garros.

"It just seemed like [the red clay] brought out every aspect of her game," Garrison said. "You know, it came to the forefront when she had to put it in place in some of those more difficult matches to win the French [Open]."

"It seemed to have a special significance for Serena because she got a place there," Rubin added. "She started spending time there in the off-season and, when you're that comfortable, in a place, definitely translates on to the tennis court."

"I think Richard realized that Venus & Serena Williams needed to develop on all courts" - Zina Garrison

Serena Williams' father Richard at the 2012 Wimbledon Championships.

Later in the podcast, Zina Garrison credited Venus and Serena Williams' father Richard for ensuring that the two were equipped to play on all surfaces and not just hardcourts.

The former World No. 4 revealed that the Williams sisters had a claycourt in their backyard that they used for training. She went on to add that Serena Williams "loved" to play on the red clay, and that the 40-year-old would herself attest to the same.

"A lot of times people didn't realize they had a clay court in their backyard, you know?" Garrison said. "And so they practice a lot on clay. I think Richard realized that, you know, they needed to develop on all courts, not just one."

"And so that was always very interesting to me," she continued. "And even if you talked to Serena now, she'll tell you, she loves playing on clay."