[3][4] In August, he made his ATP debut in the qualifying competition as a wildcard at the 2022 National Bank Open in Montreal where he defeated James Duckworth in the first round.

He defeated Liam Broady and top seed Dan Evans of Great Britain at the 2023 Surbiton Trophy.

141, Diallo defeated again Daniel Evans to win his first ATP Tour match and first at the Masters 1000 level at the 2023 National Bank Open in Toronto.

[citation needed] At the Davis Cup Finals group stage, Diallo recorded a shock upset victory over world No.

144, he also qualified for the main draw of the 2024 US Open making his debut, with wins over Sho Shimabukuro and two French players, Titouan Droguet and Valentin Royer.

[12] He defeated Jaume Munar and upset 24th seed Arthur Fils, his first two main-draw Grand Slam wins, to reach the third round for the first time in his career.