2021 Monte-Carlo Masters – Singles
| Singles | |
|---|---|
| 2021 Monte-Carlo Masters | |
| Champion | Stefanos Tsitsipas |
| Runner-up | Andrey Rublev |
| Score | 6–3, 6–3 |
| Draw | 56 (7 Q / 4 WC ) |
| Seeds | 16 |
Stefanos Tsitsipas defeated Andrey Rublev in the final, 6–3, 6–3 to win the singles tennis title at the 2021 Monte-Carlo Masters. It was his first ATP Tour Masters 1000 title, making him the first Greek to win a Masters tournament. Rublev was also in contention for his maiden Masters 1000 title.
Fabio Fognini was the defending champion from when the tournament was last held in 2019, but lost to Casper Ruud in the quarterfinals.