Albert Cesare/The Enquirer / USA TODAY NETWORK

Americans Ben Shelton and John Isner put on a show for their home crowd, as they both pulled off upsets in their respective matches on Wednesday in the second round of the Western & Southern Open in Mason, Ohio.

Playing on a wild-card entry, Shelton toppled fifth-seeded Casper Rudd of Norway 6-3, 6-3. Shelton, the reigning NCAA singles champion out of Florida, won 22 of 26 (84.6 percent) of his first-serve points while winning all nine of his service games.

At just 19 years old, Shelton is in his ATP Masters 1000 debut at the Cincinnati-area event. Although he's looked comfortable up to this point, he's still getting adjusted to playing against the best that the tour has to offer.

"I think you've got to fake it till you make it, right?" Shelton said. "If I'm not feeling completely comfortable at the beginning, I'm going to do my best to show that I am until I find myself in a place where I am settled in."

"I'm finding it an easier time the more I'm in these situations, getting my heart rate down and feeling more calm on the court."

Isner picked up a 7-6 (5), 6-7 (5), 6-2 victory over No. 8 seed Hubert Hurkacz of Poland. The second-round match had to be paused, though, when a ball boy fainted on the court, prompting both Isner and Hurkacz to offer assistance.

"From what I hear, the kid is going to be okay and hopefully he's getting some fluids and in the air conditioning right now resting up," Isner said.

No. 11 seed Taylor Fritz of the United States was also a winner, beating Australian Nick Kyrgios 6-3, 6-2. But not every American prevailed in their second-round contest, as Tommy Paul fell to Canada's Dennis Shapovalov 3-6, 6-4, 6-3, and qualifier Marcus Giron was on the losing end of a 6-3, 6-3 result with 15th-seeded Spaniard Roberto Bautista Agut.

Aside from Rudd and Hurkacz, other seeded competitors took care of business.

Fourth-seeded Stefanos Tsitsipas of Greece bested Serbian Filip Krajinovic, Russian sixth seed Andrey Rublev edged lucky loser Fabio Fognini of Italy, No. 7 seed Felix Auger-Aliassime of Canada beat Australia's Alex de Minaur and 10th-seeded Italian Jannik Sinner edged Serbian Miomir Kecmanovic after he retired in the second set.

In other action, No. 9 seed Cameron Norrie of Great Britain battled back to edge fellow countryman Andy Murray 3-6, 6-3, 6-4.

Two more matches were scheduled for the nightcap, including Spanish No. 2 seed Rafael Nadal's against Croatian Borna Coric, who is playing on a protected ranking.

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