NEW YORK -- Amanda Sobhy already is the top squash player the U.S. has ever produced.

At No. 6 in the world, the 5-foot-8 left-hander ranks higher than any other American-born athlete -- male or female -- in the history of the Professional Squash Association. And if the 23-year-old Harvard grad wins every match at New York City's Tournament of Champions starting Sunday, she may inch up the PSA rankings.

Last year, the Long Island native thrilled the home crowd (and many commuters) inside the tournament's glass court in Grand Central Terminal. Sobhy made the final, pushing current world No. 1 Nour El Sherbini to four games in the best-of-five championship match.

"I'm in it to win it this year," Sobhy says about the tournament. "That's the first thing I want to check off my box. Then I want to start breaking into the [world] top five."

Her dual aspirations are well within reach. Sobhy has beaten every player ranked above her, including the top three women in the world (all from Egypt), 2015 world champion Laura Massaro of England (No. 4) and Camille Serme of France (No. 5).

And Sobhy ("SO-bee") has only been a full-time pro for 18 months. Unlike most players on the tour, she spent four years devoted to college squash while playing pro events on the side as an amateur.

"In my family, it's always been education first," she says. "But in high school, you'd get so many conflicting views. People would be like, 'Oh, her squash is going to drop completely. She should just go on tour. Why waste the potential?' "

But Sobhy was determined to prove a point. "I knew that playing college squash and trying to keep up professionally would be extremely tough. And, in fact, it was. But I wanted to show people that, yes, you can go to a top university in the U.S. and go on the professional tour and be successful."

Her world ranking during those four years at Harvard never dipped below 30, and it was as high as 10 when Sobhy graduated in May 2015 with a degree in anthropology and a perfect 62-0 collegiate record that included four individual national championships.

According to her coaches, college squash also helped toughen her already-tenacious mental game. Throughout her entire undergraduate career, "The amount of expectation was ridiculous," recalls Harvard coach Mike Way.

Sobhy already had won four pro tournaments by the time she was 16. And on her 17th birthday, she won the 2010 junior world championship. So every time she stepped on the college court, Way says, "There was an assumption that Amanda would win -- not just by everyone on her own team, but also the opposing team. That is one big bag of stress. It's hard enough to win, let alone carry that."

And yet, in four years of collegiate play, Sobhy lost only two games -- which is akin to a college tennis player losing only two sets in four years.

"I'm always amazed by her mental strength, and I think it's because she's used to playing with pressure," says Thierry Lincou, the 2004 men's world champion and former world No. 1 from France who is the squash coach at M.I.T. and now coaches Sobhy in Boston.

The Tournament of Champions is held in a glass court inside Grand Central Terminal in New York City. Tim Clayton/Corbis/Getty Images

Sobhy grew up playing against the members of her own family as the middle child of three squash-playing siblings born to squash-loving parents. Her father, Khaled, was a junior national champion in Egypt who reached No. 30 in the world before moving to the U.S. in 1986. Her American mother, Jodie Larson, had also won a national title in the early '80s. When each child made up his or her mind to focus on squash, Khaled had them training six days a week with an occasional family tournament thrown in for "fun."

"Nobody wants to be the worst squash player in the family," Amanda says, so it was fairly intense.

Every summer until 2011, the family also would spend two months in Egypt, where the kids would play as much squash as possible against their peers in Cairo and Alexandria -- not just to hone the game's fundamentals, but also to keep pace with future champions who would eventually continue Egypt's long dominance in international squash.

Amanda's older brother, Omar, now 25, went on to compete for George Washington University. Her younger sister, Sabrina, now 20, is a sophomore on the Harvard team. The sisters' Crimson careers did not overlap, but they did face off in 2014, at the U.S. national championships in Charlottesville, Virginia, where Sabrina beat Amanda in the final in straight games -- 11-7, 11-8, 11-7 -- to become the youngest U.S. national champion in tournament history.

"Everyone was utterly shocked," Sabrina says. "As was I."

After the match Amanda told her sister, "Watch out, Beans, because you're never going to win again!" But in the next breath, she gave Sabrina full credit for playing well.

Amanda Sobhy went undefeated in college -- winning 62 matches during her four years at Harvard. Francois Nel/Getty Images

If the Sobhy sisters were to compete on the pro tour, it could go a long way toward popularizing a sport that has only 1.7 million players in the U.S. (a participation rate that trails all other racquet sports including pickleball and cardio tennis), according to 2015 data compiled by the Sports & Fitness Industry Association. In 2015, a headline in The Boston Globe fueled the hype by dubbing the Sobhy sisters "the Venus and Serena of Squash."

They wouldn't be the first sisters to reach No. 1 and 2 in the squash world. Rachael and Natalie Grinham of Australia did it. But Sabrina, who was only 18 when that article came out, says there "was definitely a lot of pressure for me to ... go pro, so we could actually be compared to them."

For now, the Harvard sophomore is content focusing only on college squash, even if it means coping with Amanda's legacy at the alma mater and deflecting questions about her own future pro career.

If Sabrina changes her mind, Amanda would relish the competition. "I tell her, 'This could be us!" Amanda says. "Just go play some professional tournaments! Please!"

Meanwhile, Amanda will focus on reaching No. 1 in the world, and if that happens, no one should be surprised. "I've talked to her plenty of times," Sabrina says, "and she's like, 'I'm not going to stop until I can get to No. 1. Yeah. I know I can do it.'

"She clearly has it in her mind that that's what she wants. She knows she's capable of doing it," Sabrina says.

"It's only going to be a matter of time," adds coach Lincou. "She's beaten every girl in the world. It's about winning titles now."