| Champ: |  Novak Djokovic |
| Runner: | Stefanos Tsitsipas |
| Score: | 6–7(6–8), 2–6, 6–3, 6–2, 6–4 |
| Draw: | 128 |
| Seeds: | 32 |
See main article: 2021 French Open.
Novak Djokovic defeated Stefanos Tsitsipas in the final, 6–7(6–8), 2–6, 6–3, 6–2, 6–4 to win the men's singles tennis title at the 2021 French Open.[1] It was his second French Open title and 19th major title overall.With this victory, he became the first man to achieve the double career Grand Slam in the Open Era,[2] and the first player in the Open Era to win a major after coming back from two sets to love down in two matches during the same major.[3] Tsitsipas became the first Greek player to reach a major final.[4] It also marked the second consecutive year a man trailed by two sets in a major final yet rallied to win, following Dominic Thiem's victory at the 2020 US Open.
Rafael Nadal was the four-time defending champion, but lost to Djokovic in a 4 hour and 11 minute epic semifinal.[5] [6] Nadal's defeat marked only his third loss out of 108 French Open matches, including his first loss in 14 semifinal appearances at the tournament.[7] It also marked the first time that Nadal lost a match at the French Open after taking the opening set,[8] and the first French Open where a player defeated Nadal and went on to win the tournament. In winning this match, Djokovic became the only man ever to defeat Nadal two times at the French Open.
Djokovic and Daniil Medvedev were in contention for the world No. 1 ranking; Djokovic retained the ranking after Medvedev lost in the quarterfinals.[9]
Nadal and Roger Federer were attempting to win a record 21st major title and become the outright leader in the men's singles major tally.[10] Federer, like Djokovic, was attempting to become the first man in the Open Era to achieve the double career Grand Slam in what would prove to be his final French Open appearance. This was the first time in major history that Djokovic, Federer, and Nadal, the three most successful men's singles major champions of all time, were in the same half of the main draw.[11] [12] After both reached the semifinals, Djokovic and Nadal met for a record-extending 58th time in the Open Era, with Djokovic emerging victorious in four sets.[13]
For the first time in the Open Era, no French players reached the third round. This tournament also marked the last time that any Grand Slam featured Nadal, Federer and Djokovic together, thus marking an end of the "Big Three" era.[14] Thiem's first-round defeat guaranteed a new French Open finalist from the bottom half of the draw; Tsitsipas ultimately emerged as that finalist. Carlos Alcaraz became the youngest player since Djokovic in 2005 to win a match at the French Open, and was also the youngest player to reach the third round at the tournament since Andrei Medvedev in 1992.[15] This was the first time since 2004 that a French Open men's singles final went to five sets; on that occasion, Gastón Gaudio also came from two sets down to win the title.[16]
The following are the seeded players. Seedings are based on ATP rankings as of 24 May 2021. Rankings and points before are as of 31 May 2021. Because the tournament was moved a week, points of the week of 10 June 2019 include results from Stuttgart and 's-Hertogenbosch.
As announced by the ATP in March 2021, tournaments from 4 March to 4 August 2019 points due to COVID ranking adjustments will count 50%, including their 2020 points whichever is greater. 2019 points which are higher will still be dropped as normal.[17] Accordingly, the higher of each player's 2019 or 2020 points will be replaced by his 2021 points at the end of the tournament. Note that this is a different ranking adjustment system than the one being used by the WTA for the women's event.
| Seed | Rank | Player | Points before | 2019 points | 2020 points | Points won | Points after | Status |
|---|---|---|---|---|---|---|---|---|
| 1 | 1 | Novak Djokovic | 11,313 | 720 | 1,200 | 2,000 | 12,113 | Champion, defeated Stefanos Tsitsipas [5] |
| 2 | 2 |  Daniil Medvedev | 9,793 | 10+10 | 10 | 360 | 10,143 | Quarterfinal lost to Stefanos Tsitsipas [5] |
| 3 | 3 |  Rafael Nadal | 9,630 | 2,000 | 2,000 | 720 | 8,630 | Semifinal lost to Novak Djokovic [1] |
| 4 | 4 |  Dominic Thiem | 8,445 | 1,200 | 360 | 10 | 7,425 | First round lost to Pablo Andújar |
| 5 | 5 | Stefanos Tsitsipas | 7,500 | 180+10 | 720 | 1,200 | 7,980 | Runner-up, lost to Novak Djokovic [1] |
| 6 | 6 | Alexander Zverev | 6,990 | 360 | 180 | 720 | 7,350 | Semifinals lost to Stefanos Tsitsipas [5] |
| 7 | 7 | Andrey Rublev | 6,090 | 0 | 360 | 10 | 5,910 | First round lost to Jan-Lennard Struff |
| 8 | 8 | Roger Federer | 5,605 | 720 | 0 | 180 | 5,065 | Fourth round withdrew due to physical condition concerns |
| 9 | 9 |  Matteo Berrettini | 3,958 | 45+250 | 90 | 360 | 4,103 | Quarterfinal lost to Novak Djokovic [1] |
| 10 | 10 |  Diego Schwartzman | 3,465 | 45 | 720 | 360 | 3,105 | Quarterfinals lost to Rafael Nadal [3] |
| 11 | 11 | Roberto Bautista Agut | 3,215 | 90 | 90 | 45 | 3,170 | Second round lost to Henri Laaksonen [Q] |
| 12 | 12 | Pablo Carreño Busta | 3,085 | 90 | 360 | 180 | 2,905 | Fourth round lost to Stefanos Tsitsipas [5] |
| 13 | 13 |  David Goffin | 2,875 | 90+45 | 10 | 10 | 2,830 | |
| 14 | 15 |  Gaël Monfils | 2,713 | 180+20 | 10 | 45 | 2,568 | Second round lost to  Mikael Ymer |
| 15 | 16 |  Casper Ruud | 2,690 | 90 | 90 | 90 | 2,690 | Third round lost to Alejandro Davidovich Fokina |
| 16 | 17 | Grigor Dimitrov | 2,521 | 90 | 180 | 10 | 2,431 | |
 Milos Raonic | 2,518 | 0+90 | 0 | 0 | 2,473 | Withdrew for personal reasons | ||
| 18 | 19 | Jannik Sinner | 2,500 | (48)† | 360 | 180 | 2,320 | Fourth round lost to Rafael Nadal [3] |
| 19 | 20 |  Hubert Hurkacz | 2,498 | 10 | 10 | 10 | 2,533 | First round lost to Botic van de Zandschulp [Q] |
| 20 | 21 | Félix Auger-Aliassime | 2,423 | 0+150 | 10 | 10 | 2,423 | |
| 21 | 22 |  Alex de Minaur | 2,350 | 45+45 | 10 | 45 | 2,350 | |
| 22 | 23 | Cristian Garín | 2,350 | 45+45 | 90 | 180 | 2,440 | Fourth round lost to Daniil Medvedev [2] |
| 23 | 25 | Karen Khachanov | 2,280 | 360+10 | 180 | 45 | 2,010 | |
| 24 | 26 | Aslan Karatsev | 2,245 | (18)† | 16 | 45 | 2,274 | Second round lost to Philipp Kohlschreiber [PR] |
| 25 | 27 |  Dan Evans | 2,195 | 10+125 | 10 | 10 | 2,106 | First round lost to Miomir Kecmanović |
| 26 | 28 | Lorenzo Sonego | 2,132 | 10 | 180 | 10 | 2,042 | First round lost to Lloyd Harris |
| 27 | 29 | Fabio Fognini | 1,933 | 180 | 10 | 90 | 1,843 | Third round lost to Federico Delbonis |
| 28 | 31 |  Nikoloz Basilashvili | 1,785 | 10+10 | 10 | 45 | 1,820 | Second round lost to Carlos Alcaraz [Q] |
| 29 | 32 | Ugo Humbert | 1,780 | 10 | 10 | 10 | 1,815 | First round lost to  Ričardas Berankis |
| 30 | 33 |  Taylor Fritz | 1,760 | 45 | 90 | 45 | 1,715 | Second round lost to Dominik Koepfer |
| 31 | 34 | John Isner | 1,730 | 0 | 45 | 90 | 1,775 | Third round lost to Stefanos Tsitsipas [5] |
| 32 | 35 | Reilly Opelka | 1,726 | 10 | 10 | 90 | 1,806 | Third round lost to Daniil Medvedev [2] |
The following players would have been seeded, but withdrew before the tournament began.
| Rank | Player | Points before | 2019 points | 2020 points | Points lost | Points after | Withdrawal reason |
|---|---|---|---|---|---|---|---|
| 14 | Denis Shapovalov | 2,780 | 10 | 45 | – | 2,780 | Shoulder injury |
| 24 | Stan Wawrinka | 2,281 | 360 | 90 | 315 | 1,966 | Foot injury |
| 30 | Borna Ćorić | 1,870 | 90+90 | 10 | 112 | 1,758 | Shoulder surgery |
The following players were awarded wild cards into the main draw.[18]
See main article: 2021 French Open – Men's singles qualifying.