We spent last week counting down our list of the top 100 athletes of the 21st century, and two women's tennis players made the list, starting with Serena Williams at No. 2 overall.
We also voted on an overall top 10 for women's tennis. Who else made the list of some of the greatest women's tennis players of the 2000s?
1. Serena Williams
Key accomplishments: 23-time major champion (second most by any player all time), women's record 365 major match wins, 73 career titles (fifth most by a woman in the Open era).
There is little that Williams didn't achieve during her record-setting career, including winning 23 major titles. But it might have been her last one that was the most improbable. She needed to win one more Grand Slam to break the tie with Steffi Graf for most in the Open era (which began in 1968) -- a mark Williams said she had been "chasing for a really long time" -- and remained in the 2017 Australian Open draw even after finding out she was pregnant shortly before competition began. She was in peak Serena form, never dropping a set en route to a final showdown with her sister Venus. She defeated Venus to take sole ownership of the record.
Williams played in four more major finals after her return from maternity leave and a complicated childbirth. She didn't win another title. "The way I see it, I should have had 30-plus Grand Slams," Williams wrote in Vogue in a 2022 essay announcing her impending retirement. "I didn't get there. ... But I showed up 23 times, and that's fine. Actually it's extraordinary." -- D'Arcy Maine
2. Venus Williams
Key accomplishments: Seven-time major singles champ, five-time Wimbledon champ, 270 major match wins (fifth most by a woman in the Open era), a record 89 career major appearances in singles.
The elder Williams sister burst onto the tennis scene as an enthusiastic and joyful teenager, and likely would have won many more titles if not for the arrival of Serena. While Williams' results have been remarkable, and she has the most major titles among active women on tour, she has been equally influential off the court as a champion for gender equality in tennis and beyond.
While advocating for equal pay at Wimbledon, Williams asked tournament officials at a meeting a simple question: "Would you want your daughter or your sister or your mother or your wife or a loved one to be a woman paid less?" Wimbledon started offering equal prize money for men and women in 2007. Williams called the achievement "the best moment of my career" in 2023. -- D'Arcy Maine
3. Maria Sharapova
Key accomplishments: Five-time Grand Slam champion, No. 1 player for a total of 21 weeks, 36 career WTA titles.
She won Wimbledon at age 17, beating Serena Williams in straight sets in the 2004 final. She was the world No. 1 by 18. She was one of the most marketable athletes in the world while she was still a teenager. And despite all the expectations and pitfalls that come with that, she managed to create a long career for herself, winning five Grand Slam titles, wrapping up a Career Slam in 2012 and finishing 10 seasons ranked in the WTA top 10. A long losing streak to Serena prevented her from racking up an all-timer's résumé -- she lost 19 straight to the GOAT, including eight straight in Slams after her Wimbledon win. But in the Open era, only 10 women have won more Slam titles. -- Bill Connelly
4. Justine Henin
Key accomplishments: Since Jan. 1, 2000: 42 WTA singles titles, 7 Grand Slam titles, Olympic gold singles medal, inducted into International Tennis Hall of Fame in 2016.
She felt like a throwback, even in the late 1990s. Standing only 5-foot-5, Justine Henin played a slice-and-dice game with speed, technique, tenacity and an utterly perfect, one-handed backhand. And even as the game was taken over by the power of the Williams sisters, Lindsay Davenport and Amelie Mauresmo, Henin landed plenty of blows. She went 23-26 against those four players, and she was 12-5 in Grand Slam semifinals and 7-5 in finals. Henin finished 2003, 2006 and 2007 ranked No. 1 in the world, and after her surprise retirement in the spring of 2008, brought on by injury and fatigue, she returned in 2010 and immediately made another Slam final as a wild card at the Australian Open. Elbow problems forced her to retire for good the next year, but her presence assured that the top of the women's game had plenty of variety for most of a decade. -- Connelly
5. Iga Swiatek
Key accomplishments: Five-time Grand Slam champion, 20 career WTA titles, current No. 1 player in the world.
The thing about ranking players based on a specific period of time is that it's hard to figure out what to do about someone like Iga Swiatek. She has already won five Slam titles and 10 WTA 1000 events; in the Open era, only Serena Williams and Steffi Graf can top her in bowl categories. She has won as many Slams as Maria Sharapova and Martina Hingis and more 1000s than Monica Seles and Venus Williams. She has definitively earned a spot on this list, but she's also just 23 years old. She's only one Slam title behind where Serena Williams was at 23. She has won as many French Opens (four) as Rafael Nadal, the king of clay, had at the same age. She hasn't even figured out grass yet. Swiatek's trajectory is unlike anything we've seen since Serena on the women's side. She's already a Hall of Famer, but she's only getting started. -- Connelly
6. Kim Clijsters
Key accomplishments: Four-time major champion in singles, 2-time major winner in doubles, 41 career titles, No. 1 in singles and doubles in 2003.
Kim Clijsters had already enjoyed a stellar career -- reaching 12 Slam semis and five finals, winning one -- when she announced her retirement in 2007 and gave birth to her daughter, Jada, in 2008. When she returned to the tour in the summer of 2009, did she ease into her comeback? Not so much. She beat top-10 opponents at each of her first two tournaments back, then beat Venus Williams, Serena Williams and Caroline Wozniacki to win the 2009 US Open almost out of the blue. She defended her title with a romp over Vera Zvonareva the next year, then won the Australian Open in 2011 too. -- Connelly
7. Naomi Osaka
Key accomplishments: Four-time Grand slam champion, finished 2019 as No. 1 player in the world.
After floating around the top 50 for a couple of years, Naomi Osaka took the world by storm at the age of 20 in 2018. She won Indian Wells to jump into the top 30. She walloped Madison Keys and Serena Williams by matching 6-2 6-4 scores to win the US Open and move into the top 10. She won the Australian Open the following year to move to No. 1. She won the US Open and Australian Open double again in 2020 and '21, all the while becoming one of the most marketable women in sports history. Battling injury and burnout, she stepped away from the tour and had her first child in 2023. Already a Hall of Famer, she returned in 2024 and nearly beat clay-court queen Iga Swiatek in the French Open. Her second chapter might end up being just as fascinating as her first. -- Connelly
8. Ash Barty
Key accomplishments: Three-time Grand Slam champion, 15 singles titles, women's world No. 1 for 121 weeks.
The 5-foot-5 Australian was the child of golfers and had the hand-eye coordination and athleticism to play any sport in the world. She chose tennis for good after dabbling in professional cricket, surged into the WTA top 20 at age 21, won three Slam titles in a nine-tournament run, finished three straight years at No. 1 ... and then retired after winning the Australian Open, her home Slam, at age 25. Her serve was far bigger than her stature, and she could win matches with either power or defense. She was absurdly well-rounded, she packed a Hall of Fame career into just about a four-year period, and then quit to have a well-rounded life. Always leave them wanting more, right? -- Connelly
9. Angelique Kerber
Key accomplishments: Three-time major champion, silver medal in 2016 Olympics, 14 career titles.
As former pro player and tennis commentator Andrea Petkovic put it in her Finite Jest newsletter, "If tennis was played from the baseline only, Angie Kerber would have been the greatest female tennis player of all times. I know that because I have played the greatest female tennis player of all times. Sadly for Angie, a serve is required in tennis." Even without an overpowering serve, Kerber rode defense and impeccable movement and anticipation to incredible heights. From 2016 to '18, she won three Slams -- two with finals victories over Serena Williams -- and reached two other semifinals. She finished 2016 ranked No. 1 in the world. After having a child in 2023, she returned to the tour in 2024 and, at age 36, with nothing more to prove, she has scored a couple of top-20 wins. -- Connelly
10. Amelie Mauresmo
Key accomplishments: Two-time major champion, 25 career titles, won Olympic silver in 2004.
Blessed with both power and perfect technique (and a level of knowledge that made her a successful coach for players such as Victoria Azarenka, Marion Bartoli and Andy Murray after retirement), Mauresmo burst onto the scene with a run to the 1999 Australian Open final at age 19. She suffered a number of close calls and heartbreaks, but late in a run of 16 quarterfinals in 19 Slams, Mauresmo finally broke through, winning both the Australian Open and Wimbledon in 2006. She finished four years in the WTA top five and seven in the top 10, and she overcame the ghosts of early failures to eventually retire triumphant. -- Connelly