1999 Mercedes-Benz Cup – Singles

Andre Agassi was the defending champion, but was defeated in the final to Pete Sampras with a score of 7–6(7–3), 7–6(7–1). By reaching the final, Sampras completed his 271st week at the world No. 1 ranking in his career, surpassing the previous record of 270 weeks established by Ivan Lendl.

1999 Hall of Fame Tennis Championships – Singles

Leander Paes was the defending champion, but lost in the quarterfinals to Wayne Arthurs

1990 Volvo San Francisco – Singles

Brad Gilbert was the defending champion, but lost in the first round to Gary Muller

1992 Volvo San Francisco – Singles

Darren Cahill was the defending champion, but did not compete this year

2005 Tippmix Budapest Grand Prix – Singles

Jelena Janković was the defending champion, but decided to compete in Stanford at the same week

1994 European Indoors – Doubles

Zina Garrison-Jackson and Martina Navratilova were the defending champions, but competed this year with different partners

1991 Volvo San Francisco – Singles

Andre Agassi was the defending champion, but lost in semifinals to Brad Gilbert

1980 Avon Championships – Singles

Martina Navratilova was the defending champion, but lost in the final against Tracy Austin. The score was 6–2, 2–6, 6–2

2004 Swisscom Challenge – Singles

Justine Henin-Hardenne was the defending champion, but did not compete this year

2004 Swisscom Challenge – Doubles

Kim Clijsters and Ai Sugiyama were the defending champions, but none competed this year. Clijsters was injured on her left wrist, while Sugiyama decided to focus on the singles tournament

1990 Estoril Open – Women's doubles

Iva Budařová and Regina Rajchrtová were the defending champions, but Rajchrtová opted to rest in order to compete at the Fed Cup the next week. Budařová teamed up with Catherine Tanvier and lost in the semifinals to Carin Bakkum and Nicole Jagerman