With her stunning upset of world No. 1 Iga Swiatek on Wednesday night in the U.S. Open quarterfinals, No. 6 Jessica Pegula advanced to her first Grand Slam semifinal.

Pegula, who had been 0-6 in major quarterfinals, scored the biggest win of her career with a dominant 6-2, 6-4 victory over the five-time major winner Swiatek, the 2022 U.S. Open champion. Pegula’s terrific summer continues after she won the Canadian Open and reached the final in Cincinnati.

Pegula, 30, is the second daughter of an American billionaire to advance to the Final Four of her home slam. No. 13 Emma Navarro, 23, will face No. 2 Aryna Sabalenka in one semifinal on Thursday; Pegula will meet the unseeded Karolína Muchová in the other. The women’s final is on Saturday.

Terry Pegula, Jessica’s father, made his fortune in oil and gas, and has since turned it into a sports empire that includes the Buffalo Bills and Buffalo Sabres. He is worth $7.7 billion, No. 373 in the world, according to Forbes.

Ben Navarro, Emma’s father, is the founder and chief executive of Sherman Financial Group, which owns the Las Vegas-based lender Credit One. He also owns the Cincinnati and Charleston tennis events, and has an estimated net worth of $1.5 billion according to Forbes.

Both Pegula and Navarro were born in New York State — Pegula in Buffalo and Navarro in Manhattan. Pegula takes the 7 train to the Open.

Tennis can be an expensive sport, but there are no shortcuts. You have to practice and put in the work. Where players like Pegula and Navarro do have a financial advantage is in paying for coaching, physio, travel, equipment and other expenses. But you can’t fake it with the actual technique.

Both players find it “annoying” when people think their family’s fortunes are responsible for their tennis success.

“I did some media thing the other day. They were, like, What’s the most annoying thing?” Pegula, who made more than $14 million from her on-court career coming into the Open, told Barron’s.

“It’s that people think I have a butler, that I get chauffeured around. I have a private limo, that I fly private everywhere. I’m definitely not like that.”

She added: “It’s a little annoying, but honestly I just think it’s kind of funny because I don’t really even know anyone that lives like that. It’s outrageous.”

As for finally breaking through to her maiden Slam semifinal, Pegula sounded very relieved.

“I’ve been so many friggin times [ to the quarterfinals] and I just kept losing but to great players, to girls who have gone on to win the tournament,” she said on court. “I know everyone keeps asking me about it but I was like, ‘I don’t know what else to do. I just need to get there again and win the match,’ so thank God I was able to do it and finally, finally I can say semifinalist.”

Navarro, the 2021 NCAA singles champion from the University of Virginia, took out defending champion and No. 3 seed Coco Gauff in the fourth round and then beat No. 26 Paula Badosa in the quarters. Afterward, she thanked her father.

“I want to thank my dad who saw a vision from when I was really Young,” Navarro told ESPN’s Rennae Stubbs. “He knew maybe I was a little bit ADHD to be sitting in a classroom or a 9-to-5, and I think he saw something in me from a young age, so thanks, dad, for sending me on this journey.”

But she later added that her wealthy childhood isn’t solely responsible for her success.

“I did have access to resources as a kid, but I don’t want that to take away from the fact that I’ve worked really, really hard to be where I’m at,” she said. “I’ve put a ton of hours in, and I started training twice a day and getting in the gym from the time I was 8, 9 years old. It’s been a ton of hard work and dedication.”

With the American duo into the women’s semis, there are now four American men and women remaining in the draws for the first time since 2003. On Friday, No. 12 Taylor Fritz and No. 20 Frances Tiafoe will face off in the first all-American Grand Slam men’s semifinal since 2006. No American man has won a major since Andy Roddick at the Open in 2003. Appropriately. Roddick was in a suite watching Pegula win her quarterfinal.

Navarro had career earnings of about $2.5 million coming into the Open.

Both she and Pegula have earned $1 million for reaching the semis. The tournament winner will take home $3.6 million, and the runner-up $1.8 million.

More important than the money for both players is the opportunity to play for a Grand Slam title — possibly against one another.

“I think deep down I do believe it [that I can win],” Navarro, who lost in the first round a year ago, told ESPN’s Nick Kyrgios after upsetting Gauff in the fourth round.

“Yeah, I think I can win it.”

Said 18-time major champion Chrissie Evert of Pegula: “She’s the best player out there who has not won a Slam. Could this be her year?”