NEW YORK — Caroline Garcia and Ons Jabeur were both 16 years old when they first played against one another at a Grand Slam event. A year later they met again with a spot in a major junior final on the line.

As heralded young players who frequently made deep runs in junior Slams, the two became very familiar with one another — ultimately meeting four times at the tournaments — and had similar sky-high expectations for their budding careers.

Their paths soon diverged, with Garcia achieving more immediate success on the WTA tour and Jabeur, who won the 2011 girls title at Roland Garros, needing years to make her major main draw debut after turning professional. But through twists and turns, and ups and downs, they will now meet on Thursday with each looking to advance to the first US Open final of their careers.

While the 2021 US Open showcased the rise of talented teenagers, including eventual champion Emma Raducanu, finalist Leylah Fernandez and quarterfinalist Carlos Alcaraz, this year’s tournament is about a slightly older generation of players who have been grinding for years. In addition to Garcia and Jabeur, now both 28, Karen Khachanov, 26, advanced to his first major semifinal on Tuesday, as did Frances Tiafoe, who is very much a veteran on tour despite being only 24, on Wednesday.

“It’s impressive because they didn’t give up, and they found a way to keep going and to not only keep playing, but keep improving,” said Alexandra Stevenson, the former Wimbledon semifinalist and current ESPN analyst. “That says a lot. And now, their experience really plays into [their current success]. It helps these players keep their calm in tough moments.

“They know how to play their game style in all circumstances. The tour is more open now and there are a lot of breakthroughs that happen at every moment, every tournament, so why not them now?”

For every young prodigy who makes a big splash, there are dozens more with similar talent and potential who never quite achieve the same success. For some, the weight of expectations becomes too much to bear, but others continue to push forward, sometimes slowly, just hoping for their one chance to put it all together when it counts.

As a 17-year-old in 2011, Garcia briefly looked poised to fall into the prodigy category. After nearly defeating Maria Sharapova in the second round of the French Open as a wild card, Garcia was suddenly on everyone’s radar. Andy Murray even tweeted she would be “number one in the world one day” during the match. But it proved to be too much, too soon for Garcia.

“It was a lot of pressure coming from actually nowhere,” Garcia said on Tuesday. “I was [ranked] 150, 200 in the world, 17 years old. My game was not ready. I was not able to play that consistent, this kind of level. The weeks after I went back trying to play the same level, but it was not possible for me.

“It was tough because people were expecting a lot. But the game, I was not ready for anything of that. It took me some time to come step by step to the top.”

Garcia eventually hit her stride, winning the doubles title at the French Open in 2016 and reaching the quarterfinals in singles at the tournament in 2017 and nabbing two 1000-level titles. She reached a career-high ranking of No. 4 in September 2018. But while getting to the top is hard, staying there might be even more difficult. Garcia couldn’t maintain her level. She failed to advance past the third round at a Grand Slam in 2019 and hadn’t made it past the round of 16 at a major since her breakthrough in Paris until this week.

Ahead of the French Open this year, Garcia was ranked No. 79 in the world. Then she won the doubles title again, which kicked off a resurgent summer. She reached the fourth round at Wimbledon, defeated world No. 1 Iga Swiatek en route to the trophy in Poland and earned the biggest singles title of her career in Cincinnati last month.

It’s clear with every postmatch celebration, in which she joyfully propels herself in the air (hence the increasingly popular #FlyWithCaro hashtag), just how much she appreciates the wins now.

“End of 2017, 2018 was [a] great year, a lot of success, [and then] yeah, I made some mistakes,” Garcia said after her quarterfinal victory. “We made some mistakes; I really hope and I think we learned from it. Now, yeah, it’s a new year, trying to learn from every challenge. I think I grow up a lot with all the challenges on and off court. Off court, it’s very important to manage all of it.”

Jabeur’s journey to Thursday’s semifinal has been equally challenging. From Tunisia, which has had little success in tennis on the global stage, Jabeur didn’t have the support of a big federation behind her like many of her peers. For years, she toiled on the ITF circuit and attempted to get through qualifying at the Grand Slams. She was successful just twice prior to the start of the 2017 season and lost in the first round at both events.

But then things started to slowly turn around. There was a third-round appearance at Wimbledon in 2017 and a run to the final at the Kremlin Cup in Russia in 2018. She put herself on the map in 2020 with a run to the quarterfinals at the Australian Open, as well as the same round in Doha and Cincinnati. Since then, she’s climbed up the rankings and won three titles. She reached a career-high ranking of No. 2 in June and her first major final at Wimbledon just weeks later.

Now, she’s onto her first US Open semifinal, and making history for Tunisia, as well as African and Arab tennis players along the way.

“[It’s been] a lot of really hard work, and I think for me I can tell you exactly [at the end] of 2019 everything clicked for me,” Jabeur said on Tuesday after her win over Ajla Tomljanovic. “I know I had the game, but just I didn’t know how really to play with the type of slicing and controlling a little bit the game.

“So for me, the point I was like sick of losing first rounds. I know I belong in [the] top 10. Since then, you know, everything started to be better. I start to believe even more.”

Khachanov, another once-promising young junior talent, won his first tour title in 2016. By the end of the 2018 season, he had won four more, including at the 1000-level Paris Masters. He reached his first major quarterfinals at Roland Garros in 2019, cracked the top 10 soon after and then struggled. Since then he made the round of 16 at a Grand Slam just once and even lost in his opener at the US Open in 2021. But with his five-set statement victory over Nick Kyrgios on Tuesday, Khachanov showed he, too, was back.

“It’s like one more step forward,” Khachanov said after the quarterfinal win. “I’m really, really happy I could do it. Also I had to face and to beat Nick, who is playing one of the best tennis again.

“It obviously was a tough match to kind of approach before … I made my first semifinal, so it’s pretty simple in my head. I’m just really happy.”

Even Tiafoe, who made his ATP debut over eight years ago, has taken a slightly longer road to his first major semifinal than many initially expected. After being the No. 2-ranked junior in the world, and having won the prestigious Orange Bowl title at 15, he was tasked with the unenviable title of being the next great hope for American men’s tennis. With that, he faced all the pressure that accompanies such a distinction. Prior to this week, he had reached the quarterfinals at a Grand Slam just once, at the 2019 Australian Open. He hasn’t won a title since his lone victory at Delray Beach in 2018.

But fueled by self-belief — and perhaps a lucky “GOAT” sweatshirt featuring images of Serena Williams that he’s been wearing before and after matches — Tiafoe has had the best run of his career in New York. He defeated 22-time major champion Rafael Nadal in the fourth round and No. 9 seed Andrey Rublev in straight sets on Wednesday to become the first American man to reach the US Open semifinals since Andy Roddick in 2006.

“You go through different stages of your life,” Tiafoe said on Wednesday. “When I came on the scene, flying up the rankings, everything was kind of good. I got a bit complacent, 2019. Took me a long time to kind of just get myself together. Obviously with the COVID rankings, stuff like that, people not losing points, that took a while as well.

“Just in general, I just got a good team around me. I started really falling in love with the process, just trying to get better. I think during that time the cameras weren’t on me, attention wasn’t on me. I was able to just kind of get better and do my own thing. I stopped trying to be the guy. Like when things were going to happen, it was going to happen. I was fine with it; I was comfortable with myself.

“Yeah, now, it’s all come to fruition.”

There are still younger players remaining in the tournament, like 19-year-old Alcaraz and 21-year-old Swiatek, and others like Aryna Sabalenka, 24, who will be playing in her third major semifinal on Thursday.

It remains to be seen if the late rise of older players will become the norm or is just a passing trend.

Stevenson isn’t sure, but she believes skill is just part of the equation.

“For sure this is motivating for other players that age,” Stevenson said. “But it’s tough. There are a lot of 27-, 28-year-olds who can break through, but it’s more than that. It’s a combination of talent, hard work, the ability to fight, and finances, which might be the hardest part to find for a lot of players. This is an expensive sport and it’s tough to stick with it without getting the big results and sponsors. But still, this has been really fun to see.”