2022: Maiden Challenger title, ATP & top 250 debut, Davis Cup champion
In August, Diallo made his ATP debut in the qualifying competition as a wildcard at the National Bank Open in Montreal where he defeated James Duckworth in the first round. [8]
Participating in the Granby Challenger as a wildcard, Diallo won 5 consecutive matches to claim his maiden title in only his fourth main-draw Challenger-level tournament. At 20 years old, he became the youngest Canadian champion on the Challenger Tour since Félix Auger-Aliassime won the Tashkent Challenger in 2018. As a result, Diallo rose to a career-high of No. 335 in the ATP rankings. [9] He finished the year at a career-high ranking of No. 224 on 21 November 2022. [10]
2023–2024: Masters, Major debut & third round, top 100, maiden ATP final
After reaching the semifinals at the Challenger in Busan, South Korea where he lost to top seed Max Purcell, Diallo made his top 150 debut in the ATP rankings on 22 May 2023. The following month, he defeated Liam Broady and top seed Dan Evans of Great Britain on grass at the Surbiton Trophy to reach the quarterfinals, losing to eventual runner-up Jurij Rodionov. [11]
In August 2023, No. 141, Diallo again defeated Dan Evans to win his first ATP Tour match and first at the Masters 1000 level at the National Bank Open in Toronto. [12] In the second round, he lost to eventual runner-up Alex de Minaur. Later that month, Diallo won the doubles title at the Winnipeg Challenger, partnering Leandro Riedi. [13]
At the Davis Cup Finals group stage in September 2023, Diallo recorded an upset victory over world No. 18 Lorenzo Musetti, winning in straight sets to give Canada the victory over Italy. [14] He won his second Challenger title at the Slovak Open and reached the top 130 on 16 October 2023. [10]
In May 2024, Diallo qualified for his first Grand Slam at the French Open, defeating Argentinians Genaro Alberto Olivieri and Marco Trungelliti and, in the third round of qualifying, Alexander Ritschard. [15] In the first round of the main draw, he lost to Kei Nishikori in five sets. [16]
In August 2024, ranked No. 144, Diallo qualified for the main draw of the US Open, making his debut, with wins over Sho Shimabukuro and two French players, Titouan Droguet and Valentin Royer. [17] He defeated Jaume Munar and upset 24th seed Arthur Fils, his first two Grand Slam main-draw wins, to reach the third round for the first time in his career. As a result he moved up 40 spots to a new career-high of world No. 103 in the rankings on 9 September 2024. [18] He lost to 14th seed Tommy Paul in four sets. [19]
In October 2024, Diallo reached his maiden ATP Tour final at the Almaty Open, defeating Christopher O'Connell, Borna Ćorić, second seed Alejandro Tabilo, [20] and fourth seed Francisco Cerúndolo. [21] He lost in the final to third seed Karen Khachanov in three sets. [22] As a result he reached the top 100 in the rankings on 21 October 2024. [23]
2025: First Major win & ATP title, top 35
Diallo made his debut at the clay Masters 1000, the Mutua Madrid Open, where he entered the main draw as a lucky loser, just as he did the previous month at the BNP Paribas Open and Miami Open. He recorded his first Masters wins on clay over Zizou Bergs, [24] fellow lucky loser Kamil Majchrzak, Cameron Norrie, and 15th seed Grigor Dimitrov (saving three match points) to reach the quarterfinals at this level for the first time in his career. As a result, he reached the top 60 in the rankings on 5 May 2025. [25] [26] [27] [28] At the 2025 French Open Diallo pulled another upset, recording his first Grand Slam clay win over 18th seed Francisco Cerúndolo, his third top-20 career win. [29]
At the 2025 Libéma Open Diallo won his maiden ATP title making him the seventh first-time ATP Tour champion for 2025. En route he defeated Australians Aleksandar Vukic, and sixth seed Jordan Thompson, saving two match points to reach the quarterfinals, recording his first ATP wins on grass. [30] He then upset third seed and top 30 player Karen Khachanov to reach his first grass court semifinal and second overall, taking his revenge for the prior year loss in the Almaty final. [31] [32] Diallo reached his second ATP final and first on grass after defeating second seed and top 20 player Ugo Humbert. He became the first Canadian men’s singles finalist in ‘s-Hertogenbosch event history. [33] He defeated Zizou Bergs in the final in straight sets and as a result reached the top 50 at world No. 44 in the singles rankings on 16 June 2025 and the top 35 on 21 July 2025. [34]
At the 2025 Wimbledon Championships, Diallo defeated Daniel Altmaier to reach the second round, [35] in which he lost to fifth seed Taylor Fritz in a five-set match lasting over three hours. [36]
Canada
