| Men's singles | |
|---|---|
| 2019 President's Cup (tennis) | |
| Champion |  Evgeny Donskoy |
| Runner-up |  Sebastian Korda |
| Final score | 7–6(7–5), 3–6, 6–4 |
Sebastian Ofner was the defending champion [1] but lost in the third round to Aleksandar Vukic.
Evgeny Donskoy won the title after defeating Sebastian Korda 7–6(7–5), 3–6, 6–4 in the final.
All seeds receive a bye into the second round.
Evgeny Donskoy (champion)
Lorenzo Giustino (second round)
Sebastian Ofner (third round)
Egor Gerasimov (quarterfinals)
Aleksandr Nedovyesov (third round)
Mirza Bašić (third round) Lucas Miedler (third round)
Chung Yun-seong (quarterfinals)
Gonçalo Oliveira (third round) Matteo Viola (quarterfinals) Jurij Rodionov (second round) Pavel Kotov (second round)
Sasikumar Mukund (second round)
Aleksandar Vukic (semifinals) Nam Ji-sung (third round)
Zhang Zhizhen (second round)| Quarterfinals | Semifinals | Final | ||||||||||||||||||
| 1 | Evgeny Donskoy | 6 | 77 | |||||||||||||||||
| Gastão Elias | 4 | 64 | ||||||||||||||||||
| 1 | Evgeny Donskoy | 3 | 6 | 77 | ||||||||||||||||
 Khumoyun Sultanov | 6 | 1 | 65 | |||||||||||||||||
| 4 | Egor Gerasimov | 78 | 61 | 4 | ||||||||||||||||
| Khumoyun Sultanov | 66 | 77 | 6 | |||||||||||||||||
| 1 | Evgeny Donskoy | 77 | 3 | 6 | ||||||||||||||||
| Sebastian Korda | 65 | 6 | 4 | |||||||||||||||||
| 8 | Chung Yun-seong | 3 | 2 | |||||||||||||||||
| 14 | Aleksandar Vukic | 6 | 6 | |||||||||||||||||
| 14 | Aleksandar Vukic | 63 | 3 | |||||||||||||||||
| Sebastian Korda | 77 | 6 | ||||||||||||||||||
| 10 | Matteo Viola | 4 | 5 | |||||||||||||||||
| Sebastian Korda | 6 | 7 | ||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 1 | E Donskoy | 6 | 6 | ||||||||||||||||||||||||
| Alafia Ayeni | 6 | 6 | A Ayeni | 2 | 3 | ||||||||||||||||||||||
| WC | S Fomin | 4 | 4 | 1 | E Donskoy | 3 | 6 | 6 | |||||||||||||||||||
| T Gabashvili | 6 | 6 | 15 | J-s Nam | 6 | 1 | 4 | ||||||||||||||||||||
 B Patael | 3 | 2 | T Gabashvili | 6 | 4 | 2 | |||||||||||||||||||||
| 15 | J-s Nam | 1 | 6 | 6 | |||||||||||||||||||||||
| 1 | E Donskoy | 6 | 77 | ||||||||||||||||||||||||
| G Elias | 4 | 64 | |||||||||||||||||||||||||
| 12 | P Kotov | 4 | 0 | ||||||||||||||||||||||||
| G Elias | 6 | 6 | G Elias | 6 | 6 | ||||||||||||||||||||||
| PR |  N Barrientos | 1 | 1 | G Elias | 3 | 6 | 78 | ||||||||||||||||||||
| ITF |  N Sánchez Izquierdo | 6 | 4 | 6 | 6 | M Bašić | 6 | 3 | 66 | ||||||||||||||||||
| Q |  L Margaroli | 3 | 6 | 3 | ITF | N Sánchez Izquierdo | 4 | 6 | 3 | ||||||||||||||||||
| 6 | M Bašić | 6 | 3 | 6 | |||||||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 4 | E Gerasimov | 7 | 6 | ||||||||||||||||||||||||
| ITF | K Kravchuk | 6 | 77 | ITF | K Kravchuk | 5 | 4 | ||||||||||||||||||||
| H Bourchier | 4 | 63 | 4 | E Gerasimov | 6 | 6 | |||||||||||||||||||||
| ITF |  Shuichi Sekiguchi | 6 | 6 | ITF | S Sekiguchi | 2 | 0 | ||||||||||||||||||||
| WC | Dostanbek Tashbulatov | 3 | 1 | ITF | S Sekiguchi | 7 | 6 | ||||||||||||||||||||
| 16 | Zh Zhang | 5 | 4 | ||||||||||||||||||||||||
| 4 | E Gerasimov | 78 | 61 | 4 | |||||||||||||||||||||||
| K Sultanov | 66 | 77 | 6 | ||||||||||||||||||||||||
| 11 | J Rodionov | 5 | 6 | 2 | |||||||||||||||||||||||
 Baptiste Crepatte | 61 | 4 | K Sultanov | 7 | 2 | 6 | |||||||||||||||||||||
| K Sultanov | 77 | 6 | K Sultanov | 6 | 6 | ||||||||||||||||||||||
| Alt |  M Vrbenský | 2 | 3 | 7 | L Miedler | 3 | 4 | ||||||||||||||||||||
| D Yevseyev | 6 | 6 | D Yevseyev | 1 | 1 | ||||||||||||||||||||||
| 7 | L Miedler | 6 | 6 | ||||||||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 8 | Y-s Chung | 6 | 4 | 6 | |||||||||||||||||||||||
| WC | A Golubev | 68 | 4 | E Leshem | 4 | 6 | 4 | ||||||||||||||||||||
| E Leshem | 710 | 6 | 8 | Y-s Chung | 63 | 7 | 6 | ||||||||||||||||||||
| A Šetkić | 4 | 6 | 4 | 9 | G Oliveira | 77 | 5 | 4 | |||||||||||||||||||
 NH Lý | 6 | 3 | 6 | NH Lý | 4 | 4 | |||||||||||||||||||||
| 9 | G Oliveira | 6 | 6 | ||||||||||||||||||||||||
| 8 | Y-s Chung | 3 | 2 | ||||||||||||||||||||||||
| 14 | A Vukic | 6 | 6 | ||||||||||||||||||||||||
| 14 | A Vukic | 6 | 2 | 6 | |||||||||||||||||||||||
 T-h Yang | 6 | 3 | 7 | T-h Yang | 3 | 6 | 4 | ||||||||||||||||||||
| A Kadhe | 2 | 6 | 5 | 14 | A Vukic | 4 | 6 | 6 | |||||||||||||||||||
 I Marchenko | 77 | 77 | 3 | S Ofner | 6 | 3 | 4 | ||||||||||||||||||||
| WC |  M İlhan | 63 | 65 | I Marchenko | 3 | 6 | 3 | ||||||||||||||||||||
| 3 | S Ofner | 6 | 3 | 6 | |||||||||||||||||||||||
| First round | Second round | Third round | Quarterfinals | ||||||||||||||||||||||||
| 5 | A Nedovyesov | 6 | 6 | ||||||||||||||||||||||||
| WC | G Lomakin | 60 | 2 |  F Mena | 3 | 2 | |||||||||||||||||||||
| F Mena | 77 | 6 | 5 | A Nedovyesov | 64 | 4 | |||||||||||||||||||||
| Sidharth Rawat | 6 | 6 | 10 | M Viola | 77 | 6 | |||||||||||||||||||||
| ITF | S Fayziev | 2 | 2 | S Rawat | 1 | 6 | 1 | ||||||||||||||||||||
| 10 | M Viola | 6 | 2 | 6 | |||||||||||||||||||||||
| 10 | M Viola | 4 | 5 | ||||||||||||||||||||||||
| S Korda | 6 | 7 | |||||||||||||||||||||||||
| 13 | S Mukund | 68 | 65 | ||||||||||||||||||||||||
| A Rinderknech | 6 | 6 | A Rinderknech | 710 | 77 | ||||||||||||||||||||||
| Q | V Manafov | 4 | 3 | A Rinderknech | 77 | 3 | 4 | ||||||||||||||||||||
| S Korda | 5 | S Korda | 65 | 6 | 6 | ||||||||||||||||||||||
| ITF | E Tiurnev | 1r | S Korda | 7 | 6 | ||||||||||||||||||||||
| 2 | L Giustino | 5 | 3 | ||||||||||||||||||||||||
Defending champion Rafael Nadal successfully defended his title, defeating David Ferrer in the final, 7–6(7–1), 7–5. It was his record-extending seventh title at the Barcelona Open.
Tobias Kamke was the defending champion but was defeated by Evgeny Donskoy in the semifinals.
Donskoy won the title by defeating Jan-Lennard Struff 6–2, 4–6, 6–1 in the final.
Stan Wawrinka was the defending champion, but chose not to participate this year.
Nick Kyrgios was the defending champion, but lost in the semifinals to Jo-Wilfried Tsonga.
Evgeny Donskoy was the defending champion but lost in the quarterfinals to Egor Gerasimov.
Alexander Zverev defeated Dominic Thiem in the final, 6–4, 6–4 to win the men's singles tennis title at the 2018 Madrid Open.
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.
Ričardas Berankis was the defending champion but lost in the semifinals to Kamil Majchrzak.
Adrián Menéndez Maceiras was the defending champion but lost in the third round to Lucas Miedler.
Alex de Minaur was the defending champion but chose not to defend his title.
Lloyd Harris was the defending champion but chose not to defend his title.
Hubert Hurkacz was the defending champion but chose not to defend his title.
Rogério Dutra Silva was the defending champion but chose not to defend his title.
Antoine Hoang was the defending champion but chose not to defend his title.
This was the second of two editions of the tournament in the 2021 tennis season. Mackenzie McDonald was the defending champion but lost in the second round to Tomáš Macháč.
Matteo Berrettini defeated Cameron Norrie in the final, 6–4, 6–7(5–7), 6–3, to win the singles tennis title at the 2021 Queen's Club Championships. Berrettini's win earned him his fourth career ATP Tour singles title, his first ATP 500 victory, and also made him the first player to win the tournament on their main draw debut since Boris Becker in 1985. Norrie was contesting for his first title in his fourth career final.
Alex de Minaur was the reigning champion from when the tournament was last held in 2019, but chose not to participate this year.
Nick Kyrgios was the reigning champion from when the tournament was last held in 2019, but lost in the first round to Mackenzie McDonald.
Cameron Norrie defeated Nikoloz Basilashvili in the final, 3–6, 6–4, 6–1 to win the men's singles tennis title at the 2021 Indian Wells Masters. It was his first ATP Tour Masters 1000 title, and he became the first Briton to win the title. Basilashvili became the first Georgian to reach a Masters-level final since Alex Metreveli in 1968, and the first to do so while representing Georgia as an independent nation.
John Millman was the defending champion, but lost in the quarterfinals to James Duckworth.