A nervous Arthur Ashe Stadium exhaled when Jannik Sinner sealed a 4-6, 6-3, 3-6, 7-6(5), 6-4 victory over Ben Shelton on Saturday, a match that both exposed vulnerabilities in the world No. 3 and underscored why he remains a leading figure in men’s tennis. The fourth-round berth came after 4 hours and 12 minutes of high-octane baseline rallies, booming serves and momentum swings, with Sinner surviving a late break and converting on his third match point.

Shelton, the 21-year-old American whose explosive serve and aggressive net play have made him a home-court darling, repeatedly put Sinner under pressure. He opened with an early break and won the first set before Sinner steadied himself, using his improved return game to seize the second. The fourth set became the match’s emotional fulcrum; Sinner saved two set points in the tiebreak and leaned on an increasingly tense serve to force a decider.

“You have to fight in matches like this. He played great, I had to dig deep,” Sinner said afterward. “It’s never easy to play here against someone who serves like him and moves so well. I’m happy I stayed in the points and found a way.”

Statistically, the match highlighted the modern game’s dual demands. Shelton led with 18 aces to Sinner’s 14 and won more free points on serve, but Sinner’s 55 winners and 37 forced errors — coupled with 8 of 12 break points saved — proved decisive in crucial moments. Both players showed the endurance and shot-making that have defined the sport’s youth wave: power serving, aggressive baseline play, and tactical shifts mid-rally.

Beyond the court, the contest has commercial and cultural significance. Sinner, now a poster child for Italian tennis, carries substantial endorsement appeal in Europe and beyond, and deep runs at Grand Slams amplify that value. For American tennis, Shelton’s performance is another data point in the U.S. search for a new generation of men who can challenge consistently in majors. “This is a message match,” an ATP analyst noted after the match. “It tells sponsors, broadcasters and national federations where the attention will be.”

The U.S. Open’s economic engine — bolstered by sellout nights, streaming audiences and lucrative advertising — thrives on these narratives. Close matches between rising stars drive ratings, social engagement and the premium fees broadcasters can command, a reminder that individual performances translate quickly into industry momentum.

There are also social undercurrents. Sinner’s rise has heightened tennis’s profile in Italy, inspiring academies and participation among younger players, while Shelton’s emergence feeds into conversations about athletic development pathways in the United States. The match also raised the perennial questions about scheduling and player workload; five-set matches in brutal late-summer heat continue to prompt debate among players, coaches and medical staff about safety and longevity.

Sinner will now turn toward the fourth round, where he will face the winner of Sunday’s matchup between [opponent] and [opponent]. For now, he rides the mixture of relief and renewal that comes from surviving a scare, a reminder that in today’s men’s game, margins are thin and the stakes — sporting, commercial and cultural — are large. Follow The Post’s live updates from the U.S. Open in Queens for continued coverage throughout the weekend.