Daniil Medvedev defeated Reilly Opelka in the final, 6–4, 6–3 to win the men's singles tennis title at the 2021 Canadian Open. It was his fourth ATP Masters 1000 title and 12th career title. Opelka was contesting his maiden Masters 1000 final.
Rafael Nadal was the two-time reigning champion from when the event was last held in 2019 and was vying to tie Ivan Lendl's record of six Canadian Open titles, but did not participate due to a foot injury.
Seeds All seeds received a bye into the second round.
Draw
Finals
Top half
Section 1
Section 2
Bottom half
Section 3
Section 4
Qualifying
Seeds
Qualifiers
Lucky losers
Qualifying draw
First qualifier
Second qualifier
Third qualifier
Fourth qualifier
Fifth qualifier
Sixth qualifier
References
External links Main draw Qualifying draw