1990 ATP Championship Series, Single Week Singles Singles

| Tournament | Surface | Week | Winner_and_score | Finalist | Semifinalists |
|---|---|---|---|---|---|
| Indian Wells | Hard | March 5 | Stefan Edberg (2) 6–4, 5–7, 7–6, 7–6 | Andre Agassi (6) | Boris Becker (1) Jim Courier |
| Miami | Hard | March 12 | Andre Agassi (5) 6–1, 6–4, 0–6, 6–2 | Stefan Edberg (3) | Emilio Sánchez (15) Jay Berger (7) |
| Monte Carlo | Clay | April 23 | Andrei Chesnokov (12) 7–5, 6–3, 6–3 | Thomas Muster | Henri Leconte (WC) Emilio Sánchez (7) |
| Hamburg | Clay | May 7 | Juan Aguilera 6–1, 6–0, 7–6 | Boris Becker (1) | Henri Leconte (WC) Guy Forget |
| Rome | Clay | May 14 | Thomas Muster (10) 6–1, 6–3, 6–1 | Andrei Chesnokov (8) | Emilio Sánchez (4) Andrés Gómez (3) |