John McEnroe was the defending champion but lost in the quarterfinals to Kevin Curren. Curren also defeated Jimmy Connors in the semifinal and became the first player ever to defeat both Connors and McEnroe in the same Grand Slam tournament.
Pat Cash was the defending champion but lost in the quarterfinals to Boris Becker.
Boris Becker defeated the defending champion Stefan Edberg in the final, 6–0, 7–6(7–1), 6–4 to win the Gentlemen's Singles tennis title at the 1989 Wimbledon Championships.
Johan Kriek was the defending champion, but lost in the quarterfinals to Mats Wilander.
Jimmy Connors was the defending champion, but he was defeated by his rival John McEnroe in the semifinals, in what would be the last match between the two players in a Grand Slam singles tournament.
John McEnroe was the defending champion but did not compete that year.
John McEnroe was the defending champion but lost in the quarterfinals to Joakim Nyström.
Anders Järryd was the defending champion but did not compete that year.
Boris Becker was the defending champion but did not compete that year.
John McEnroe successfully defended the singles title at the U.S. Pro Indoor for a third tournament in a row, defeating Miloslav Mečíř in the final in three straight sets.
Ivan Lendl was the defending champion, but lost in the final this year.
Ivan Lendl was the defending champion, but did not participate this year.
John McEnroe was the defending champion.
Peter Fleming and John McEnroe were the defending champions, but did not participate this year.
John McEnroe was the defending champion, but did not participate this year.
John McEnroe was the defending champion, but did not participate this year.
Mats Wilander was the defending champion, but lost in the final this year.
Jimmy Connors was the defending champion, but lost in the semifinals this year.
John McEnroe was the defending champion, but did not participate this year.
Peter Fleming and John McEnroe were the defending champions, but lost in the semifinals to Pat Cash and John Fitzgerald.
