| Men's singles | |
|---|---|
| 1989 New South Wales Open | |
| 1988 Champion |  John Fitzgerald |
| Champion |  Aaron Krickstein |
| Runner-up |  Andrei Cherkasov |
| Final score | 6–4, 6–2 |
John Fitzgerald was the defending champion but did not compete that year.
Aaron Krickstein won in the final 6–4, 6–2 against Andrei Cherkasov.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.
Henri Leconte (first round) Andrei Chesnokov (first round) Aaron Krickstein (champion)
Jonas Svensson (first round) Darren Cahill (first round)
Christo van Rensburg (quarterfinals) Wally Masur (quarterfinals) Magnus Gustafsson (second round)Defending champion Jim Courier successfully defended his title, defeating Petr Korda in the final, 7–5, 6–2, 6–1 to win the men's singles tennis title at the 1992 French Open.
Pete Sampras defeated Andre Agassi in the final, 6–4, 6–3, 6–2 to win the men's singles tennis title at the 1990 US Open. It was his first major title, and the first of a then-record 14 men's singles major titles overall.
Pete Sampras was the defending champion and won in the final 5–7, 6–3, 6–3 against Andre Agassi.
Jaime Yzaga was the defending champion, but lost in the first round this year.
Miloslav Mečíř was the defending champion, but lost in the first round to Richey Reneberg.
Alberto Mancini was the defending champion, but lost in the second round this year.
The singles competition of the 1990 Cincinnati Open was a tennis tournament played on outdoor hard courts. It was the 91st edition of the tournament and was part of the 1990 ATP Tour. It took place in Cincinnati, Ohio, United States from August 06 through August 12, 1990. Brad Gilbert was the defending champion but Stefan Edberg defeated him 6–1, 6–1 in the final.
Ivan Lendl was the defending champion, but did not compete that year.
Boris Becker was the defending champion but Stefan Edberg took the title after Becker had to withdraw injured in the final at 3–3.
Amos Mansdorf was the defending champion but lost in the first round to Michael Chang.
Boris Becker was the two-time defending champion but lost in the third round to Jay Berger.
Boris Becker was the defending champion but did not compete that year.
José Luis Clerc was the defending champion but did not compete that year.
Andre Agassi won in the final 6–2, 6–4 against Paul Annacone.
Mikael Pernfors was the defending champion but lost in the quarterfinals to Brad Gilbert.
Andre Agassi was the defending champion but lost in the semifinals to Ivan Lendl.
Top-seeded Ivan Lendl overcame the defending champion, Andrés Gómez, in the final to claim his fifth title of the year and $51,000 prize money.
