Serena Williams defeated Martina Hingis in the final, 6–3, 7–6(7–4) to win the women's singles tennis title at the 1999 US Open. It was her first major singles title, the first of an eventual Open Era joint-record six US Open titles, and the first of an eventual Open Era record 23 major singles titles. Williams became the first African American woman in the Open Era to win a singles major.
Venus Williams defeated Lindsay Davenport in the final, 6–4, 7–5 to win the women's singles tennis title at the 2000 US Open. It was her second major singles title, and she became the second woman to win Wimbledon, the Olympics, and the US Open in the same season.
Steffi Graf defeated Martina Hingis in the final, 4–6, 7–5, 6–2 to win the women's singles tennis title at the 1999 French Open. It was her Open Era record-extending 22nd and final major singles title, and she equaled Chris Evert's record of nine French Open final appearances. Graf also became the first player in the Open Era to defeat the top-three ranked players at the same major; defeating world No. 2 Lindsay Davenport in the quarterfinals, No. 3 Monica Seles in the semifinals and No. 1 Hingis in the final. Hingis was attempting to complete the career Grand Slam in singles.
Venus Williams defeated the defending champion Lindsay Davenport in the final, 6–3, 7–6(7–3) to win the ladies' singles tennis title at the 2000 Wimbledon Championships. It was her first major singles title. Williams lost only one set during the entire tournament, to Martina Hingis in the quarterfinals.
Lindsay Davenport defeated the three-time defending champion Martina Hingis in the final, 6–1, 7–5 to win the women's singles tennis title at the 2000 Australian Open. It was her first Australian Open title and her third and last major singles title. She did not lose a set during the tournament. Hingis' loss ended her 27-match win streak at the Australian Open, dating back to 1997.
Defending champion Venus Williams defeated Justine Henin in the final, 6–1, 3–6, 6–0 to win the ladies' singles tennis title at the 2001 Wimbledon Championships. It was her second Wimbledon singles title and third major singles title overall.
Defending champion Martina Hingis won the women's singles tennis title at the 2000 Canadian Open after Serena Williams retired from the final due to a left foot injury, with the score at 0–6, 6–3, 3–0.
Serena Williams defeated Kim Clijsters in the final, 4–6, 6–4, 6–2 to win the women's singles tennis title at the 2001 Indian Wells Open. This would be the final time Williams would attend the Indian Wells Open until 2015, due to a boycott of the tournament by both Williams sisters in protest of racist remarks by crowd members; Venus Williams would return to the tournament until 2016.
Lindsay Davenport defeated the defending champion Martina Hingis in a rematch of the previous year's final, 6–4, 6–2 to win the singles tennis title at the 1999 WTA Tour Championships.
Defending champion Venus Williams defeated her sister Serena in the final, 6–1, 4–6, 6–4 to win the women's singles tennis title at the 1999 Miami Open.
Martina Hingis defeated Lindsay Davenport in the final, 6–3, 6–2 to win the women's singles tennis title at the 2000 Miami Open. She did not lose a set, and lost only 21 games, en route to the title.
Venus Williams defeated Martina Hingis in the final, 6–3, 6–4 to win the singles tennis title at the 1999 European Indoor Championships.
There was no defending champion, due to the cancellation of the semifinals in 1998 due to rain.
Serena and Venus Williams defeated Lindsay Davenport and Corina Morariu in the final, 6–2, 4–6, 6–4 to win the women's doubles tennis title at the 2001 Australian Open. It was the Williams sisters' fourth major doubles title, and they completed the career Golden Slam in doubles with the win.
Lindsay Davenport defeated Martina Hingis in the final, 4–6, 6–4, 6–0 to win the women's singles tennis title at the 2000 Indian Wells Masters.
The 1999 Pilot Pen Tennis singles was the singles event of the seventeenth edition of the final tournament in the US Open Series. Steffi Graf was the reigning champion, but had retired after the TIG Classic.
Sandrine Testud was the defending champion, but was defeated by Martina Hingis in the semifinals.
The 1999 Advanta Championships of Philadelphia singles was the tennis singles event of the seventeenth edition of the Advanta Championships of Philadelphia; a WTA Tier II tournament held in Philadelphia. Steffi Graf was the defending champion but retired after Wimbledon earlier in the year.
Serena Williams and Venus Williams were the defending champions, but did not compete this year.
Martina Hingis and Anna Kournikova were the defending champions, but none of them competed this year.
Serena Williams 
Julie Halard-Decugis 
