Direct answer: Stefanos Tsitsipas won the singles title at the 2021 Monte-Carlo Masters.
Context and quick details:
- Final result: Stefanos Tsitsipas def. Andrey Rublev, 6–3, 6–3 in the championship match.[5]
- The event was held at Monte-Carlo Country Club, Roquebrune-C Cap-Martin, France, with the 2021 edition succeeding the 2019 event after a pandemic pause.[1][5]
- Defending champion Fabio Fognini was eliminated in the quarterfinals by Casper Ruud.[1]
If you’d like, I can also pull a concise timeline of Tsitsipas’s path to the title (round by round) or provide notable highlights from the tournament.[5]