On 12 August 2020, Marquinhos scored a late equalizer against Atalanta in the Champions League quarter-finals, sparking a late comeback for PSG to win 2–1. On 18 August, Marquinhos scored in a 3–0 win over RB Leipzig in the semi-finals of the competition, which saw PSG reach the Champions League final for the first time in its history. PSG eventually lost out 1–0 to Bayern Munich on 23 August.