Rafael Nadal has won the French Open nine times leading to a fourth-round match against American Jack Sock on Monday. (Yoan Valat/EPA)

Nine-time French Open champion Rafael Nadal is the King of Clay for many reasons. His lasso-like lefty forehand is one of the best ever. His mental toughness is off the charts. In the best-of-five set format, his unyielding physicality sets him apart. In Paris, he has another secret weapon: real estate. No major show court plays as spaciously as the French Open’s main stadium, Court Philippe Chatrier, where the Spaniard’s defensive skills come to life. “It’s like the Maracana,” said three-time French Open champion Gustavo Kuerten, drawing an analogy to the giant Rio de Janeiro soccer stadium in his native Brazil. That advantage could be increasingly important in the week ahead.

Nadal, coming off his shakiest clay-court season in a decade, normally would spend the rest of the tournament on Chatrier, including Monday’s fourth-round meeting with 22-year-old American Jack Sock. Because of Sunday’s rain, which postponed several matches, they are slated for the smaller Court Suzanne Lenglen.

The extra space on Chatrier allows Nadal to do what he does best: roam several feet behind the baseline and dig balls out of corners; return serve deep in the court where he can take massive swipes at the ball; and generally make offensive-minded players miserable.

“For an opponent playing against Nadal on Chatrier, it seems that you have to put double as much effort than any other court in the world, because it’s so much space and it feels like you can’t make a winner,” said No. 1 Novak Djokovic, who could face No. 6 seed Nadal in a blockbuster quarterfinal. “He’s getting [to] every single ball.”

Nadal has lost just once in a decade at Roland Garros, where he is 69-1. In best-of-five set matches on clay, he’s 92-1.

It’s no coincidence that he has been most dominant here.

Nadal said Saturday that, were it his choice, he would play every match on a court that accentuates his instincts — where he can slide further, scamper longer and lace zingers from far behind the baseline.

“It’s obvious that a big court helps a little bit more my game and for the opponent is a little bit more difficult to attack, to see the clear winner,” said Nadal, who has won 14 majors.

Chatrier was built in 1928 to accommodate the Davis Cup glory years of France’s Four Musketeers and was renamed for an influential president of the French Tennis Federation.

It is the smallest of the four Grand Slam show courts; it holds 14,800 fans.

Around the edges separating the singles lines from the stands — the region where players can stretch, skim and leap to track down balls — it more than makes up for its lack of size (and no small irony considering the scarce elbow room around the overcrowded grounds).

With 32 feet behind the baseline, Chatrier is more spacious than both Wimbledon’s Centre Court and the U.S. Open’s Arthur Ashe Stadium (27 feet each). It is roughly the same as Melbourne’s Rod Laver Arena (32 and 33 feet at either end).

At the sides, where players move laterally, Chatrier provides 21 feet to maneuver, equivalent to Centre Court (22 feet) and Ashe Stadium (17 and 21 feet on either side) but slightly smaller than Laver (25 feet).

This plentiful real estate is amplified on clay, the slowest surface. More time and more space means extra time to defend. The upshot: Chatrier plays even more generously than its physical attributes might suggest.

“It feels like there is a mile of open court,” said Mike Bryan, a two-time French Open doubles champion with twin brother Bob Bryan.

With the infrastructure for retractable roofs overhead, Centre Court and Laver Arena appear snugger, several players said. On the flip side, the soaring 22,500-seat Ashe Stadium — the largest of the four Grand Slam show courts — has a diminishing effect when it comes to on-court visuals.

In contrast, Chatrier looks wider and longer and can cause players to press.

“Sometimes you overhit,” said Cedric Pioline, a 1998 French Open semifinalist and former top-five player from France.

Many players also say Chatrier is drier and faster than Lenglen, the French Open’s second-biggest court, which is built on top of a parking facility and tends to retain moisture, which slows the ball down.

The dehydrated surface helps Nadal’s biting topspin kick up more.

Others, including Nadal, say Chatrier is breezy, much like the hulking Ashe at the U.S. Open in Queens. That is another potential advantage since Nadal’s spiraling shots have more margin when they cross the net.

“Rafa is the best clay-court player ever and this is the best court for him,” said retired Frenchman Fabrice Santoro, who does TV commenting and on-court interviews at Roland Garros. “Everything is perfect for him.”

As if that were not enough, no player is more familiar with Chatrier than Nadal. He has contested 55 of 70 matches at Roland Garros there, or nearly 80 percent, including his sole defeat in 2009.

Sweden’s Robin Soderling, playing a high-risk brand of fireball tennis, defeated Nadal in the fourth round that year.

Second seeded Roger Federer, the 2009 champion, said it took him time to get used to the abundant boundaries of Chatrier. Even today, the offensive-minded Swiss must remind himself to stay forward.

“It just felt like there is so much space behind and on the sides that naturally you have a tendency to go backwards,” he said. “It’s weird to explain.”

Nadal, who will turn 29 on Wednesday, is expected back on his favorite court just in time.

The Spaniard arrived in Paris last week on the heels of his worst season on clay since 2003, two years before he won his first French Open.

He failed to win a title on European dirt and lost five times — more defeats than the entire five-year period from 2006 to 2010.

But through three rounds here, he has yet to drop a set, including Saturday’s 6-1, 6-3, 6-2 third-round thrashing of Russia’s Andrey Kuznetsov — a match he played on the cozier Lenglen.

Nadal called his play “solid” and “consistent” and seemed satisfied.

He can’t win forever, of course.

Kuerten, in town Saturday to promote his new autobiography, said if Nadal manages to capture a 10th title, Chatrier will be a factor.

“Every single piece of sand of the court matters,” Kuerten said.