As the stars of tennis were converging on the French Open and settling with their entourages into bio-secured hotels, Daniel Altmaier was already grafting on the clay courts of Paris, getting dirty in the dust while picking up clues here, tips there about the surface's quirks, and fighting like a man in a hurry through qualifying to reach the main draw.

Now there, with his until-now largely unknown name in the main-draw mix with the rich and famous, the 22-year-old German is proving as stubbornly hard to remove as the courts' ochre brick-dust on fresh linen.

Sets lost on his way to the fourth round of his debut Grand Slam tournament: Zero.

Italy's Matteo Berrettini reacts after losing his second set against Germany's Daniel Altmaier in the third round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Saturday, Oct. 3, 2020. (AP PhotoChristophe Ena)

Italy's Matteo Berrettini reacts after losing his second set against Germany's Daniel Altmaier in the third round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Saturday, Oct. 3, 2020. (AP PhotoChristophe Ena)

Nerve-testing tie-breakers won: All three.

“I keep going,” the 186th-ranked player said Saturday after his latest upset victory, a 6-2, 7-6 (5), 6-4 humbling of seventh-seeded Italian Matteo Berrettini.

And the bonus: A mention in the history books for the German who has fought back from injuries and developed a thick tennis skin on the sport's lower-level circuits. His participation in Paris was in doubt until late, when he was cleared to play after picking up an injury the preceding week.

Germany's Daniel Altmaier comforts Italy's Matteo Berrettini, left, after winning his third round match of the French Open tennis tournament in three sets, 6-2, 7-6 (7-5), 6-4, at the Roland Garros stadium in Paris, France, Saturday, Oct. 3, 2020. (AP PhotoChristophe Ena)

Germany's Daniel Altmaier comforts Italy's Matteo Berrettini, left, after winning his third round match of the French Open tennis tournament in three sets, 6-2, 7-6 (7-5), 6-4, at the Roland Garros stadium in Paris, France, Saturday, Oct. 3, 2020. (AP PhotoChristophe Ena)

With his win on Court Philippe Chatrier, its new roof open under what began as glorious and crisp autumnal blue skies, Altmaier joined two other Roland Garros debutants — Sebastian Korda and Jannik Sinner — in round four. That many men haven’t gone that far on their debuts at Roland Garros since four first-timers were among the last 16 in 1994.

Korda, the son of 1998 Australian Open champion Petr Korda, like Altmaier also took the long route through qualifying. Altmaier was just months old and 20-year-old Korda wasn't even born when Roland Garros last saw multiple men advance from qualifying into round four in 1998.

The women's draw also has two qualifiers into round four, both also shining on their Roland Garros debuts: Nadia Podoroska and Martina Trevisan.

So unfamiliar is all this to Altmaier that when retired French star Fabrice Santoro came out to conduct his post-match interview on Chatrier, the newbie said: “It's nice to meet you.”

His fourth-round opponent will be Pablo Carreno Busta, seeded 17th. He beat fellow Spaniard Roberto Bautista Agut, seeded 10th, 6-4, 6-3, 5-7, 6-4 on Saturday.

He will be the third seeded player that Altmaier has faced. Altmaier beat No. 30 Jan-Lennard Struff in round two.

"I’m a machine," Altmaier said after that win. He meant it jokingly. But his regularity on clay is becoming no laughing matter for his opponents.

Also in action Saturday in third-round play in the men's draw is top-seeded Novak Djokovic. He can overtake Roger Federer's mark of 71 matches won at Roland Garros by beating 153rd-ranked Daniel Galan of Colombia. Only 12-time French Open champion Rafael Nadal has more: 96 and counting.

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