On 18 September 2020, Müller scored his first goal of the season, and provided one assist, in an 8–0 win over Schalke 04. He later managed to win the UEFA Super Cup and DFL-Supercup to be his 27th trophy of his club career; hence, he became the most decorated player in German history, breaking the previous record of 26 trophies won by his former Bayern teammate Bastian Schweinsteiger. On 11 February 2021, he tested positive for COVID-19 and went into quarantine; hence, could not play in the 2020 FIFA Club World Cup Final.