Pablo Carreño Busta was the defending champion, but lost to Daniil Medvedev in the second round.
Rafael Nadal defeated Stefanos Tsitsipas in the final, 6–2, 7–6(7–4) to win the men's singles tennis title at the 2018 Rogers Cup. It was his fourth Canadian Open title.
Novak Djokovic defeated Roger Federer in the final, 6–4, 6–4 to win the men's singles tennis title at the 2018 Cincinnati Masters. With the win, he became the first player to complete the career Golden Masters in singles.
Roberto Bautista Agut was the defending champion, but withdrew before the tournament began.
Dominic Thiem defeated Roger Federer in the final, 3–6, 6–3, 7–5 to win the men's singles tennis title at the 2019 Indian Wells Masters. It was his maiden ATP Tour Masters 1000 title, and he became the first Austrian to win a Masters title since Thomas Muster won the 1997 Miami Open.
João Sousa was the defending champion, but lost in the second round to David Goffin.
Marin Čilić was the defending champion, but lost in the second round to Diego Schwartzman.
Dominic Thiem was the defending champion, but he chose not to defend his title this year.
Roger Federer was the defending champion, but chose not to participate this year.
Defending champion Rafael Nadal defeated Daniil Medvedev in the final, 6–3, 6–0 to win the men's singles tennis title at the 2019 Canadian Open. It was the first time Nadal successfully defended a hard court title.
The 2019 Chengdu Open was a men's tennis tournament played on outdoor hard courts. It was the 4th edition of the Chengdu Open and part of the ATP Tour 250 series of the 2019 ATP Tour. It took place at the Sichuan International Tennis Center in Chengdu, China, from September 23 to 29.
Daniil Medvedev defeated Alexander Zverev in the final, 6–4, 6–1 to win the singles tennis title at the 2019 Shanghai Masters. He did not drop a set en route to the title.
Stefanos Tsitsipas was the defending champion, but chose not to defend his title.
Alexander Bublik was the defending champion but chose not to defend his title.
Alexander Zverev defeated Matteo Berrettini in the final, 6–7(8–10), 6–4, 6–3 to win the men's singles tennis title at the 2021 Madrid Open. It was Zverev's fourth Masters 1000 title, his first since Madrid 2018, and his 15th career ATP Tour singles title overall. Berrettini was in contention to become the second Italian to be a Masters 1000 champion.
Rafael Nadal defeated the defending champion Novak Djokovic in the final, 7–5, 1–6, 6–3 to win the men's singles tennis title at the 2021 Italian Open. It was his record-extending 10th Italian Open title and record-equaling 36th Masters 1000 title overall. Nadal saved two match points en route to the title, in his third round match against Denis Shapovalov. This was also the fourth time that Nadal had won a tournament on 10 or more occasions, making him the only tennis player with the feat.
Hubert Hurkacz was the reigning champion from when the tournament was last held in 2019, but chose not to participate this year.
Novak Djokovic defeated the defending champion Daniil Medvedev in the final, 4–6, 6–3, 6–3 to win the singles tennis title at the 2021 Paris Masters. It was his record-extending sixth Paris Masters title and record-breaking 37th ATP Tour Masters 1000 title overall, surpassing Rafael Nadal's tally in the latter category.
Carlos Alcaraz defeated Pablo Carreño Busta in the final, 6–3, 6–2 to win the singles tennis title at the 2022 Barcelona Open. Alcaraz saved two match points en route to the title, in the semifinals against Alex de Minaur. With the win, Alcaraz entered the top 10 in rankings for the first time in his career, becoming the youngest man to do so since Rafael Nadal in 2005.
Novak Djokovic defeated Carlos Alcaraz in the final, 5–7, 7–6(9–7), 7–6(7–4) to win the men's singles tennis title at the 2023 Cincinnati Masters. He saved a championship point en route to his third Cincinnati Masters title and record-extending 39th ATP Tour Masters 1000 title overall; it was his ninth career title won after saving match points during a tournament. At 3 hours and 49 minutes, this match was the longest best-of-three-sets ATP Tour final and the longest match in the tournament's history.
Pablo Carreño Busta 
Alexander Bublik 
