When Serena Williams played the final match of her historic career at last year's U.S. Open, countless headlines heralded the legacy that she, as a Black woman, left on the sport of tennis.
Four Black American players -- Coco Gauff, Frances Tiafoe, Madison Keys and Ben Shelton -- reached the quarterfinals of the Grand Slam tournament, the first time that has happened in the sport's open era, which began in 1968.
Gauff and Keys both reached the semifinals on the women's side, and are playing different opponents, meaning the U.S. Open women's final could feature two Black American female players.
Their potential meeting would come 22 years after the Williams sisters made history as the first two women of color to compete in the U.S. Open women's final, in 2001.
On the men's side, Shelton, whose father Bryan Shelton was also a groundbreaking Black American tennis professional, will play Friday in his first-ever Grand Slam singles semifinal, facing off against No. 2 seed Novak Djokovic.
Shelton moved onto the semifinals after beating Tiafoe Tuesday in four sets in the quarterfinals, in a match described by the U.S. Tennis Association's general manager of player development Martin Blackman as a "watershed moment" for American tennis
The match was the first time in U.S. Open history that two Black men faced off in a men's quarterfinal match.
"Watching Ben and Frances on that stage and connecting the dots between them playing on Arthur Ashe Stadium, in a facility that's named after Billie Jean King, in a year that we're celebrating 50 years of equal prize money, with a beautiful bust of Althea Gibson just outside, it made me think of the legacy and the pioneers and the people that had sacrificed and opened doors for all of us, and created these opportunities for Ben and Frances and Coco and so many others," Blackman, himself a Black former professional tennis player, told "Good Morning America." "Obviously it wasn't the finals, but it was a watershed moment for American tennis."
Prior to the match, Tiafoe, the tournament's No. 10 seed, described facing off against his friend Shelton as a "monumental moment." The court the two players competed on is of course named after Arthur Ashe, the late tennis star and civil rights champion who was the first Black man to win the U.S. Open, in addition to winning Wimbledon and countless other titles.
"Two people of color playing in the quarterfinals, huge match on Arthur Ashe. It's a pretty monumental moment," Tiafoe said in a press conference. "I'm pretty excited to compete against him. Hopefully it's a great battle."
The success of Tiafoe, ranked No. 10 in the world, is an example of efforts over the past two-plus decades to transform tennis from a predominantly white, country-club sport into one that is accessible to all, according to Blackman.
Tiafoe, who last year made history as the first Black American man to reach the U.S. Open semifinals since Ashe in 1972, got his start playing tennis as a kid at the Junior Tennis Champions Center in College Park, Maryland, where his dad, an immigrant from Sierra Leone, worked in maintenance and construction.
The JTCC is considered a center of excellence in the USTA's National Junior Tennis and Learning program, which provides tennis and educational opportunities to kids in underserved communities
"One of the most powerful and impactful things that the USTA does is to administer a network of about 150 tennis and education programs throughout the country, mostly in inner-cities, for kids to be able to have a safe place to go, be physically active, learn tennis, get tutoring and to use tennis as a vehicle to get to college," said Blackman, adding of the JTCC in particular, where he previously worked as director, "They are developing hundreds of kids every year, and that's where Frances got his start."
Blackman said the success people are seeing now in players like Tiafoe as well as Gauff, Shelton, Keys, Taylor Townsend, Chris Eubanks and more is also the result of a new approach to player development the USTA started in 2009, when, outside of the Williams sisters, American tennis was at a low. At that time, the USTA began to work with private-sector coaches and began to offer camps at the local, regional and national levels to develop more players from all backgrounds.
"Those camps were the vehicle not only for evaluating players, but really building relationships with their parents and their coaches and delivering education," Blackman said. "And player development was not cookie-cutter but really dependent on the on the unique needs of every player and the recognition that every player is different."
Blackman said that among American players, anyone ranked in the top 100 today and under the age of 26 came through that new pathway of development.
"We kind of look back to that 2009 to the end of 2019 period as building the house," he said. "And now we're so excited to be reaping the fruit of that work."
Blackman acknowledged that even with all the best development efforts, progress is not made without representation.
He said the USTA has put a focus internally on diversifying to recruit more female, Black and Hispanic coaches, saying, "We need our coaching community, just like our playing community, to look like America."
On the players' side, the so-called "Williams sister effect" has undoubtedly helped lead to the surge of Black players in tennis, at all levels, according to Blackman.
Serena Williams stepped away from tennis last year at the age of 40 after a record-breaking, decades-long professional career that saw her win 23 Grand Slam singles titles. Venus Williams, a winner of seven Grand Slam singles titles, continues to play professional tennis today at the age of 43.
"At the end of the day, when families are choosing a sport, when they're thinking about what sport to put their daughter or their son in, it's really because they're attracted to something for some reason," Blackman said. "And the Venus and Serena effect has pulled so many girls of color into the sport that it's just been a game-changer."
He continued, "It's been a trajectory-changing period of 20 years when girls of color and girls in general, regardless of color, have been able to look up to Venus and Serena, and see two authentic women who are proud of who they are and are representing themselves as strong Black champions. There's no substitute for that."
When Serena Williams played her last match last year, Gauff, now America's young Black tennis phenom, reflected on how much of an impact she had on players like herself.
"Growing up, I never thought that I was different because, you know, the No. 1 player in the world was somebody who looked like me," Gauff told NPR, referring to Serena Williams. "A lot of times, being a woman in the world, a Black woman in the world, you kind of settle for less. And I feel like Serena just taught me that from watching her. She never settled for less. I can't think of a moment in her career, in her life, that she settled for less."
The Williams sisters have had an impact on the men's side too, according to Blackman, along with Black male players ranging from MaliVai Washington and James Blake to Shelton's dad Bryan, who was a record-breaking college tennis coach before stepping down earlier this year to coach his son's professional career.
The result of tennis becoming more diverse is that it has also become more culturally relevant, with tennis stars on the covers of magazines and featured on shows like Netflix's "Breaking Point." Blackman said this era of American tennis reminds him of the 1970s -- when Ashe was dominant but largely alone on tour as a Black American player -- but greatly improved.
"In the late '70s, tennis was so cool and so relevant," Blackman said. "This time around, it's the same energy, it's the same momentum, but it's so much more diverse."