Alexander Zverev is climbing the short-list of players who could thwart Rafael Nadal's quest for a record-extending 11th French Open title.
Despite having never played a five-set match at Roland Garros before this year, the second-seeded German has shown mettle and a cool head to win two of them back-to-back.
He is shifting his 6-foot-6 (1.98-meter) frame around the red dust with increasing comfort. And he is into the fourth round for the first time.
Zverev saved a match point in a 6-2, 3-6, 4-6, 7-6 (3), 7-5 win over Damir Dzumhur on Friday. The victory was the 21-year-old German's first on Court Philippe Chatrier, and he immediately got a taste for it.
"Hopefully many more to come," he said in his post-match on-court interview.
Also through is Novak Djokovic, shaking off the rust of his enforced absence from the tour with an elbow injury.
The 2016 champion beat 13th-seeded Roberto Bautista Agut of Spain 6-4, 6-7 (6), 7-6 (4), 6-2, in a near four-hour match too sluggish for Djokovic's liking. After losing a point during the second-set tiebreaker, the 20th-seeded Djokovic angrily whacked his racket into the clay.
"He plays with a lot of patience," he said of Agut, "too much for me."
Djokovic's fourth-round opponent is Fernando Verdasco. The 30th seed from Spain beat fourth-seeded Grigor Dimitrov, a two-time Grand Slam semifinalist, 7-6 (4), 6-2, 6-4.
In the women's draw, second-seeded Caroline Wozniacki breezed past French wild-card entry Pauline Parmentier 6-0, 6-3 and appears to be brimming with self-belief after her breakthrough Australian Open title in January.
One of the few lulls in Zverev's high-intensity match came when Dzumhur collided with a ball boy after winning the third set.
The chunky Bosnian and the ball boy were both looking skyward at a ball when they ran into each other. For a few anxious moments, the ball boy seemed hurt, lying on the dirt. But he picked himself up with Dzumhur's help, and play resumed.
After Zverev ran away with the first set, Dzumhur produced an array of deft drop shots to drag the lanky German to the net, where he was less effective.
Zverev, so relaxed early on that he laughed when he completely missed a service return, lost his air of confidence, swapping it for an increasingly grim look of determination. He won just 29 of 67 points he contested at the net and didn't appreciate Dzumhur's use of the short ball.
"The drop shots he was hitting were kind of ridiculous," he said.
Dzumhur had match point on Zverev's serve at 5-4 in the final set.
Zverev broke serve in the next game. This time, the Bosnian player's use of drop shots backfired. Having again forced Zverev to the net, he watched helplessly as his German rival volleyed a forehand past him.
Zverev then held serve to secure his spot in the fourth round, the second time he's got that far at a major. The first occasion was at Wimbledon last year.
He was also 0-7 against top 50 players at majors before beating the 29th-ranked Dzumhur.
"It was important to kind of see for myself that I can win back-to-back five-set matches," Zverev said. "That gives me a lot of confidence going deep into the fifth set, going long matches on this kind of surface, and knowing that I'm fit enough to last as long as I want."
Zverev has never been seeded as high as No. 2 at a major. It is the first time since the 2006 Australian Open that someone other than Nadal, Djokovic, Roger Federer and Andy Murray has been among the top two seeds at a major.
So far, he's living up to the billing.