PARIS — Roland Garros keeps changing look and shape in the 21st century. It is vaster and more avant-garde, and perhaps it will become less crowded in the passageways as tennis fans shuffle from match to match.

The No. 1 Court, known as the bullring, will soon be demolished. The No. 2 Court, with its enchanting lack of symmetry, is already gone.

Even the main Philippe Chatrier Court, where Rafael Nadal won his 12th French Open singles title on Sunday, was reconstructed in the past year.

It might be hard to believe at this stage, but Nadal will fade from view someday, too. Or at least he’ll spend men’s final day in the front row of the presidents box, his water bottles surely still in order, instead of in the arena with his socks coated in red clay and his poor opponents failing to find, to use one of his favorite English words, solutions.

But for now, and for honestly who knows how much longer, Nadal, 33, remains a pillar of the place: more immovable, as it turns out, than many a stadium.

[Ashleigh Barty won the women’s title. Read about how she did it.]

He has cemented his reputation and legacy year after year, duel after duel, rout after rout. He added another layer of mortar on Sunday by holding off Dominic Thiem, 6-3, 5-7, 6-1, 6-1, in what was a dazzler of a final for exactly two high-powered, spectacularly athletic sets.

“The first set was unbelievably intense; the second as well,” Thiem said. “Maybe I had a little drop in the third set, I don’t know, but against other players, it’s not that dramatic, a little drop like that physically and also tennis-wise. But him, such a great champion, he uses the situation and goes all in.”

Nadal has been giving it all in Paris and elsewhere since 2005, and he is now 12-0 in finals at Roland Garros. That is not a typo. His only two losses at any stage at this event came in the fourth round in 2009 to Robin Soderling and in the quarterfinals in 2015 to Novak Djokovic. (In 2016, he withdrew with an injury after the second round.)

It sounded more like a mantra than a question, and well before Santoro finished off the list, Nadal was scratching the back of his head and looking slightly embarrassed. He has such gaudy stats, yet away from the clay he is more into understatement. But awkward moments are his own fault for enduring and winning beyond any reasonable expectation.

“I can’t explain it,” Nadal said. “My feeling for me is it’s a dream. When I played the first time here in 2005, I could not think that I’d be coming back here in 2019.”

Much less still winning in 2019, but on he reigns. If they are not going to retire the trophy and give Nadal the Coupe des Mousquetaires permanently (not a bad idea), it must surely be in need of repair at this stage after all the celebratory bites he has taken out of it.

Such outrageous dominance has not been to the liking of those who prefer a healthy dose of suspense, but it is one of the most remarkable achievements in the history of professional sports.

“For sure, you are not going to see another guy win 12 French Opens,” said Nicolás Massú, Thiem’s coach.

Nadal has doubled Bjorn Borg, the greatest men’s clay-court player before him, who won six times in Paris. And he has, more intriguingly, closed the gap with his friendly rival Roger Federer, who has won a men’s record 20 Grand Slam singles titles. Nadal now has 18.

“It’s a motivation, but it’s not my obsession,” Nadal said of the record. “It’s not what makes me get up every morning or go and train and play. I don’t think my inner happiness or my future will change if I equal Federer or if I do something like Djokovic. I have already achieved more in my career than I ever imagined.”

This latest title in Paris was far from a given. Nadal withdrew from the BNP Paribas Open before a semifinal match with Federer in March with a recurrence of knee tendinitis. The withdrawal, the latest in a long line during the last two injury-filled seasons, sent him into a funk.

“I lost a little bit that energy because I had too many issues in a row,” he said, throwing shadow punches at himself to demonstrate. “Is tough when you receive one, then another. Then sometimes you are groggy.”

But after failing to win titles on clay in Monte Carlo, Barcelona or Madrid, he returned to top gear to win the Italian Open and dropped only two sets at Roland Garros.

The fourth-seeded Thiem, a 25-year-old Austrian who lost to Nadal in straight sets in last year’s final, was playing for the fourth day in a row. A full day of rain on Wednesday had muddled the schedule, and he had needed parts of two days to finish his semifinal against the top-ranked Djokovic.

That match ended 23 hours before Sunday’s began. If Thiem was fatigued, it did not show in the taut, thrilling first set. Then he prevailed in the second.

But Nadal, the No. 2 seed, won the first 11 points of the third set and quickly went ahead by two breaks, 3-0. After the grueling duels of the first two sets, which each had taken nearly an hour, Nadal won the third set in 28 minutes.

Thiem had chances to break Nadal in the hard-fought first and third games of the fourth set but could not convert. Thiem, looking lower on energy and inspiration, could not hold his own, and Nadal soon ran out the match, mixing successful forays to the net with his customary precision and court coverage at the baseline.

The tournament ended with a forehand return from Thiem that landed just long. Nadal, tracking it closely, watched it bounce and then went into a slide and landed on his back, arms spread wide and eyes closed.

He was undeniably a man on his element. Nadal is the first player in any era to win 12 singles titles at the same Grand Slam tournament, breaking his tie with Margaret Court, the Australian who won the Australian Championships (which later became the Australian Open) 11 times from 1960 to 1973.

But nothing in men’s tennis can compare, and perhaps Massú is correct that nothing ever will truly compare. Nadal, a man who runs (and runs) on doubt, is skeptical.

“I consider myself a normal person,” he said before Sunday’s triumph. “I’m certain that another player can do it in the future. But it’s true that you need to have qualities, luck, physical attributes and a long enough career to do it. You need to have the possibility to play at least 11 French Opens to win 11 times. It’s complicated.”

Even more complicated when his successors will need to play at least 12 French Opens to win 12 times.