|- style="background:#fbb" | 134 || September 1 || Giants || 2–7 || Atlee Hammaker (2–0) || Charles Hudson (8–10) || Mark Grant (1) || 20,528 || 72–62 |- style="background:#bfb" | 135 || September 2 || Giants || 8–3 || Shane Rawley (10–6) || Jeff Robinson (7–14) || None || 20,529 || 73–62 |- style="background:#fbb" | 136 || September 3 || Cubs || 3–4 (12) || George Frazier (7–4) || Renie Martin (1–2) || Lee Smith (29) || 28,162 || 73–63 |- style="background:#fbb" | 137 || September 4 || Cubs || 2–7 || Scott Sanderson (7–4) || Steve Carlton (11–7) || None || 25,054 || 73–64 |- style="background:#fbb" | 138 || September 5 || @ Cardinals || 5–6 || Dave Rucker (2–3) || Al Holland (5–10) || None || 13,171 || 73–65 |- style="background:#fbb" | 139 || September 6 || @ Cardinals || 5–6 || Bob Forsch (2–4) || Bill Campbell (6–5) || Bruce Sutter (39) || 14,524 || 73–66 |- style="background:#fbb" | 140 || September 7 || @ Expos || 1–7 || Bryn Smith (11–11) || Shane Rawley (10–7) || None || 15,182 || 73–67 |- style="background:#fbb" | 141 || September 8 || @ Expos || 0–4 || Steve Rogers (6–13) || John Denny (6–6) || None || 18,140 || 73–68 |- style="background:#bfb" | 142 || September 9 || @ Expos || 6–5 (11) || Larry Andersen (3–3) || Joe Hesketh (1–1) || Kevin Gross (1) || 31,348 || 74–68 |- style="background:#fbb" | 143 || September 10 || @ Cubs || 2–3 || Tim Stoddard (9–5) || Jerry Koosman (14–12) || Lee Smith (31) || 26,083 || 74–69 |- style="background:#bfb" | 144 || September 11 || @ Cubs || 6–3 || Charles Hudson (9–10) || Lee Smith (9–6) || Al Holland (29) || 28,964 || 75–69 |- style="background:#bfb" | 145 || September 12 (1) || Cardinals || 3–1 || Shane Rawley (11–7) || Kurt Kepshire (4–5) || None || see 2nd game || 76–69 |- style="background:#bfb" | 146 || September 12 (2) || Cardinals || 6–5 || Tug McGraw (2–0) || Bruce Sutter (5–5) || None || 18,811 || 77–69 |- style="background:#bfb" | 147 || September 13 || Cardinals || 10–2 || John Denny (7–6) || Joaquín Andújar (19–12) || None || 16,787 || 78–69 |- style="background:#bfb" | 148 || September 14 || Expos || 9–5 || Steve Carlton (12–7) || Steve Rogers (6–14) || None || 18,194 || 79–69