Àlex Corretja defeated Carlos Moyá in the final, 3–6, 3–6, 7–5, 6–3, 7–5 to win the singles tennis title at the 1998 ATP Tour World Championships.

The final was a rematch of that year's French Open final, where Moyá prevailed.

[1] Pete Sampras was the two-time defending champion, but was defeated in the semifinals by Corretja.

Standings are determined by: 1. number of wins; 2. number of matches; 3. in two-players-ties, head-to-head records; 4. in three-players-ties, percentage of sets won, or of games won; 5. steering-committee decision.

Standings are determined by: 1. number of wins; 2. number of matches; 3. in two-players-ties, head-to-head records; 4. in three-players-ties, percentage of sets won, or of games won; 5. steering-committee decision.