On October 1, 2020, making his first postseason appearance, Anderson earned the win against the Cincinnati Reds, clinching the Wild Card Series for the Braves. He became the youngest pitcher in MLB postseason history to allow fewer than three hits while striking out nine while pitching at least six innings. In the NLDS game on October 7, Anderson threw 5.2 innings and got 9 strikeouts as the Braves beat the Miami Marlins 2–0.
