Jo-Wilfried Tsonga was the defending champion, but withdrew before the tournament began.
The 2018 Gazprom Hungarian Open was a men's tennis tournament played on outdoor clay courts. It was the 2nd edition of the Hungarian Open, and part of the ATP World Tour 250 series of the 2018 ATP World Tour. It took place at Nemzeti Edzés Központ in Budapest, Hungary, from April 23–29.
Lucas Pouille was the defending champion, but lost in the second round to John Millman.
Peter Gojowczyk was the defending champion, but lost to Kei Nishikori in the second round.
This article displays the qualifying draw for men's singles at the 2019 Australian Open.
Mirza Bašić was the defending champion but lost in the first round to Martin Kližan.
Karen Khachanov 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.
The 2019 Hungarian Open was a men's tennis tournament to be played on outdoor clay courts. It was the 3rd edition of the event, and part of the ATP Tour 250 series of the 2019 ATP Tour. It took place at Sport 11 in Budapest, Hungary, from April 22–28.
The 2019 French Open – Men's Singles Qualifying was a series of tennis matches which took place from 20–24 May 2019 to determine the sixteen qualifiers into the main draw of the 2019 French Open – Men's singles. Five players also qualified as lucky losers.
Marco Cecchinato was the defending champion, but lost in the first round to Aljaž Bedene.
The 2019 St. Petersburg Open was a tennis tournament played on indoor hard courts. It was the 24th edition of the St. Petersburg Open, and part of the ATP Tour 250 Series of the 2019 ATP Tour. It took place at the Sibur Arena in Saint Petersburg, Russia, from September 16 through 22, 2019.
The 2019 US Open – Men's Singles Qualifying is a series of tennis matches that takes place from 19 August 2019 to 23 August 2019 to determine the sixteen qualifiers into the main draw of the 2019 US Open – Men's singles, and, if necessary, the lucky losers.
Dominic Thiem was the defending champion and chose not to defend his title, as he was still competing at the 2020 US Open.
Matteo Berrettini defeated Aslan Karatsev in the final, 6–1, 3–6, 7–6(7–0) to win the men's singles tennis title at the 2021 Serbia Open.
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.
Miomir Kecmanović was the defending champion, but chose to compete at the Summer Olympics instead.
Jannik Sinner was the defending champion and successfully defended his title, defeating Gaël Monfils in the final, 6–3, 6–4.
Andrey Rublev was the reigning champion from when the tournament was last held in 2019, but lost to Adrian Mannarino in the second round in a rematch of the 2019 final.
Matteo Berrettini 
Filip Krajinović 
