ゲリー・ウェバー・オープン
Following the clay season, Monfils quickly turned to the grass. At the 2021 Halle Open, Monfils continued to struggle as he lost in the opening round to Lloyd Harris. Following this, Monfils quickly turned to the next event of the 2021 Eastbourne International. He lost in the opening round again, this time to qualifier Max Purcell.