Jessica Pegula’s U.S. Open is over, ended by Aryna Sabalenka.

But the American heiress’ climb up the rungs of the tennis world is very much alive.

No, Pegula didn’t have the raw force to match Sabalenka’s howitzer of a forehand, or enough weaponry to win Saturday’s final in Flushing Meadows. The world’s second-ranked player hit 40 aces and overpowered her in one or two key moments to edge out a 7-5, 7-5 win.

What Pegula has shown is the determination to improve, and the willingness to work.

A 30-year-old late bloomer who had never reached a Grand Slam semifinal before this week, Pegula will finish the U.S. Open as a finalist, the third-ranked player in the world, and living proof that sweat equity goes a long way.

“My movement and my serve has gotten a little bit better. So there are certain parts that maybe are a little bit more consistent than they used to be,” Pegula said. “As far as a baseline, [my serve] is not as much up and down throughout the weeks and through matches. I’d say the same for my movement.

“The ball, am I seeing it like a watermelon every single day? Not quite. But I think with those other things, maybe that’s why it may seem like I’m playing my best tennis.”

For the first time in her career, Pegula has shown that her best can contend for a Slam.

“I’m more than sure one day you’re going to get one,” Sabalenka said during the trophy ceremony, adding “Maybe more. But start with one.”

And that’s the thing. Pegula, who admitted she’s fought through periods where she questioned whether she even wanted to play, is now not only playing but still getting better at the age when some are hanging it up.

World No. 1 Iga Swiatek — who Pegula drilled 6-2, 6-4 in the quarterfinals — is just 23, as is fellow American semifinalist Emma Navarro.

And Pegula’s doubles partner Coco Gauff — who won last year in Flushing — is the epitome of a phenom, still just 20.

But Pegula is 30, roughly the same age that saw Danielle Collins and Garbine Muguruza retire, and two years older than Ashleigh Barty. But she switched coaches this year, remade her body, is still working and fine-tuning around the margins. And getting confidence from that work, and the ensuing results.

“Oh, yeah. If I can’t take confidence from this, there’s got to be something wrong. I’ve taken confidence from winning a 250, from winning a 1000, from being able to win another 1000, multiple ones now. Then to be able to be a Grand Slam finalist, that was kind of the last thing for me. I made a lot of quarterfinals, but can I make a semi? Can I be a contender to actually win a Grand Slam.

“For sure I will take a lot of confidence from this in maybe an hour or two, because I’m kind of annoyed. … I’m just annoyed I lost right now. Everyone is like, ‘Congrats, amazing tournament.’ I’m like, ‘Eh, whatever.’ ”

Pegula has definitively answered whether she can compete for a Slam.

If anything, compete is what she does best.

Pegula has shown the determination to improve from being ranked just 125th six years ago, and a modest 62nd at the end of 2020. Even after taking the hard leap into the top-10, for Pegula that wasn’t enough. That’s not shocking.

The daughter of Terry and Kim Pegula — billionaire owners of the Buffalo Bills and Sabres — she was never going to settle for mediocrity.

Pegula has acknowledged that her father pushed her to do well on the court. She credits her calm, cool demeanor to her mother — the mother that nearly died from a June 2022 cardiac arrest, that just in July publicly took steps outside her vehicle — assisted by Terry — and broke down the Bills’ huddle to end training camp that day.

And on Saturday, Pegula said her parents were both in Arthur Ashe Stadium to see her big moment.

Pegula showed fight that would make her mother proud. She contended for a Grand Slam title.

Next up will be winning one.

“She’s a very ambitious young lady, and she felt that she had the tools to [win a Slam],” coach Mark Knowles told the Post. “But it takes another level of belief. And I think she’s there.”