(CNN) For a long time we've assumed Roger Federer is the greatest player of his generation -- perhaps all time -- but Rafael Nadal's 11th French Open reboots the conversation.
The Spaniard edged to 17 grand slam titles with victory over Dominic Thiem at Roland Garros, just three short of Federer's mark.
Pure numbers aren't the whole story, and supporters of both will speak about the merits of style and other artistic nuances, but they provide a solid starting point for discussion.
And with Nadal at world No.1, fit, totally dominant in Paris, and four years younger than the still-hungry Federer, it's game on.
The two 30-somethings should be in the twilight of their careers, but they could just be entering the defining era.
Some will say 11 wins on the same surface skews Nadal's credentials, but the counter argument is that Federer has won a record eight Wimbledons.
Nadal insists he is not "crazy" about record collecting and denies he is on a quest to beat the Swiss, but he says he wouldn't mind joining him on 20 grand slam titles either.
"You can't be frustrated if somebody has more money than you, if somebody has a bigger house than you, if somebody has more grand slams than you," he told reporters in Paris.
"You can't live with that feeling. You have to do your way. I'd love to have 20 like Roger in the future or more, but it is not something in my mind. I know I've had an amazing career so I want to keep fighting for these things."
READ: Why Rafael Nadal is so good on clay
READ: Federer on retirement: 'I'm looking forward to it'
Having won all four grand slams at least once Nadal is in exalted company. Since the Open era began in 1968, only Nadal, Federer, Djokovic and Andre Agassi have clinched a career grand slam.
Even the great Pete Sampras, a seven-time Wimbledon champion and third on the list of Open-era grand slam winners, couldn't achieve it. Nor, for that matter, could Bjorn Borg, John McEnroe, Jimmy Connors, Ivan Lendl and Boris Becker.
Nadal may only have a singular Australian Open triumph to date, but then Federer and Djokovic have only won one French Open each.
The 36-year-old Federer, who won his latest grand slam in Australia in January, skipped Paris this time to focus on the grasscourt season.
This year marks the 10th anniversary of the epic Federer-Nadal five-set Wimbledon final thriller -- often thought of as the greatest tennis match ever.
Sport does have a compelling habit of throwing up neat narratives -- a repeat in July could once again alter the grand slam landscape.
READ: Why Nadal is all at sea during his time off
READ: Meet the superfans who worship at the altar of Federer
When compared by tournament, Nadal's superiority on the red clay is clear.
While Federer and Djokovic have both won six Australian Opens, and Federer recently overhauled Sampras' seven at Wimbledon, and three players share five US Open wins, the Spaniard is head and shoulders above the rest in Paris.
Nadal made his name by winning at Roland Garros on his debut as a 19-year-old in 2005. Since then he has only lost twice -- to Swede Robin Soderling in 2009 and to Djokovic in 2015. That's 86 wins out of 88 matches.
READ: Meet the veteran tennis photographer snapping the stars
If you take Borg's six French Open titles out of the equation, the next best Paris performers are miles behind which further reinforces Nadal's achievements.
Even in the women's game no one can get close to him, with American Chris Evert leading the way on seven French Open titles.
It's hard to believe that as of this year Nadal has only played 79 matches on grass and from those he has garnered two Wimbledon titles.
That in itself should show he is a bona fide all-court player.
So what makes Nadal so good on clay? Former Wimbledon champion Pat Cash offered a few theories while working for CNN's Open court at Roland Garros.
"We have never seen a player hit so much top spin before," said the Australian.
"The power he puts into the shots and the top spin is just very, very hard to control on a slow court over five sets."
Then there is Nadal's athleticism
"He's unbelievably fast, and he can keep going forever, which helps on the clay," adds Cash.
"He keeps getting the ball back, his speed and athleticism is just phenomenal.
"His footwork on the clay is amazing, I don't think I've ever seen anybody move that quick on the clay."
And there is the mindset.
"Mentally, he's just ferocious," said Cash.
"Clay is one of the toughest surfaces to be successful at, because you have to be focused all the time, the momentum can change very quickly."
The "King of Clay" could yet be the king of the tennis world.