| Singles | |
|---|---|
| 2017 Amex-Istanbul Challenger | |
| Champion |  Malek Jaziri |
| Runner-up |  Matteo Berrettini |
| Final score | 7–6(7–4), 0–6, 7–5 |
Malek Jaziri was the defending champion and successfully defended his title.
Jaziri won the title after defeating Matteo Berrettini 7–6(7–4), 0–6, 7–5 in the final.
Malek Jaziri (champion)
Denis Istomin (quarterfinals, retired)
Marius Copil (first round)
Evgeny Donskoy (quarterfinals)
Alexander Bublik (semifinals) Matteo Berrettini (final) Luca Vanni (withdrew)
Stefanos Tsitsipas (first round)| Semifinals | Final | ||||||||||||
| 1 | Malek Jaziri | 6 | 4 | 6 | |||||||||
 Karim-Mohamed Maamoun | 2 | 6 | 1 | ||||||||||
| 1 | Malek Jaziri | 77 | 0 | 7 | |||||||||
| 6 | Matteo Berrettini | 64 | 6 | 5 | |||||||||
| 6 | Matteo Berrettini | 7 | 6 | ||||||||||
| 5 | Alexander Bublik | 5 | 3 | ||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | M Jaziri | 6 | 78 | ||||||||||||||||||||||||
| Q |  Marc Sieber | 2 | 66 | 1 | M Jaziri | 3 | 78 | 7 | |||||||||||||||||||
 B Bonzi | 6 | 61 | 6 | B Bonzi | 6 | 66 | 5 | ||||||||||||||||||||
| J Eysseric | 3 | 77 | 4 | 1 | M Jaziri | 6 | 64 | 6 | |||||||||||||||||||
 M İlhan | 2 | 6 | 6 | M İlhan | 2 | 77 | 0 | ||||||||||||||||||||
| T Kamke | 6 | 2 | 3 | M İlhan | 6 | 7 | |||||||||||||||||||||
| C İlkel | 2 | 6 | 4 | LL | S Dzhanashia | 2 | 5 | ||||||||||||||||||||
| LL | Shalva Dzhanashia | 6 | 2 | 6 | 1 | M Jaziri | 6 | 4 | 6 | ||||||||||||||||||
| 3 | M Copil | 2 | 5 | K-M Maamoun | 2 | 6 | 1 | ||||||||||||||||||||
| M Janvier | 6 | 7 | M Janvier | 68 | 6 | 5 | |||||||||||||||||||||
| WC | Muhammet Haylaz | 61 | 5 | WC | A Çelikbilek | 710 | 0 | 7 | |||||||||||||||||||
| WC | A Çelikbilek | 77 | 7 | WC | A Çelikbilek | 2 | 4 | ||||||||||||||||||||
 R Ortega Olmedo | 4 | 3 | K-M Maamoun | 6 | 6 | ||||||||||||||||||||||
| K-M Maamoun | 6 | 6 | K-M Maamoun | 6 | 3 | 6 | |||||||||||||||||||||
 U Ignatik | 6 | 1 | 6 | U Ignatik | 3 | 6 | 2 | ||||||||||||||||||||
| 8 | S Tsitsipas | 4 | 6 | 3 | |||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 6 | M Berrettini | 7 | 6 | ||||||||||||||||||||||||
 R Berankis | 5 | 1 | 6 | M Berrettini | 6 | 6 | |||||||||||||||||||||
| S Robert | 66 | 3 | Q | R Kern | 4 | 4 | |||||||||||||||||||||
| Q | R Kern | 78 | 6 | 6 | M Berrettini | 6 | 6 | ||||||||||||||||||||
 M Bašić | 3 | 6 | 7 | 4 | E Donskoy | 2 | 4 | ||||||||||||||||||||
| Q |  Y Mertens | 6 | 3 | 5 | M Bašić | 1 | 4 | ||||||||||||||||||||
| T Gabashvili | 4 | 1r | 4 | E Donskoy | 6 | 6 | |||||||||||||||||||||
| 4 | E Donskoy | 6 | 4 | 6 | M Berrettini | 7 | 6 | ||||||||||||||||||||
| 5 | A Bublik | 6 | 7 | 5 | A Bublik | 5 | 3 | ||||||||||||||||||||
| WC | MN Türker | 2 | 5 | 5 | A Bublik | 2 | 6 | 6 | |||||||||||||||||||
| A Šetkić | 2 | 3 | S Bolelli | 6 | 0 | 1 | |||||||||||||||||||||
| S Bolelli | 6 | 6 | 5 | A Bublik | 3 | ||||||||||||||||||||||
| WC | A Yüksel | 1 | 3 | 2 | D Istomin | 2r | |||||||||||||||||||||
| Q | R Safiullin | 6 | 6 | Q | R Safiullin | 3 | 6 | 63 | |||||||||||||||||||
| V Millot | 64 | 0r | 2 | D Istomin | 6 | 3 | 77 | ||||||||||||||||||||
| 2 | D Istomin | 77 | 0 | ||||||||||||||||||||||||
Dominik Meffert was the defending champion but decided not to participate.
Tatsuma Ito won the title, defeating Malek Jaziri 6–7(5–7), 6–1, 6–2 in the final.
Go Soeda successfully defended his title, defeating Malek Jaziri 6–1, 3–6, 7–5 in the final.
Ivo Minář was the defending champion but decided not to participate.
Gastão Elias won the title by defeating Rogério Dutra da Silva 4–6, 6–2, 6–0 in the final.
Blaž Kavčič was the defending champion, but chose not to compete.
Paul Capdeville won the final 6–2, 6–2 against Renzo Olivo.
Frank Dancevic was the defending champion, but decided to compete for the Philadelphia Freedoms of the World TeamTennis instead.
Mikhail Kukushkin was the defending champion, but did not take part this year.
Mikhail Youzhny was the defending champion but lost to Thomaz Bellucci in the first round.
Steve Darcis was the defending champion, but lost in the second round. Malek Jaziri won the title defeating Igor Sijsling in the final 5–7, 7–5, 6–4
Rajeev Ram was the defending champion but chose not to participate.
Ruben Bemelmans was the defending champion, but decided not to defend his title.
Thiago Monteiro was the defending champion but chose not to defend his title.
Marsel İlhan was the defending champion but lost in the first round to Illya Marchenko.
Norbert Gombos was the defending champion but lost in the first round to Corentin Moutet.
Mathias Bourgue was the defending champion but lost in the second round to Constant Lestienne.
Rafael Nadal was the defending champion but withdrew with a knee injury before the tournament began.
Fabio Fognini was the defending champion, but chose not to defend his title.
This was the first edition of the tournament.
Corentin Moutet was the defending champion but chose not to defend his title.
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.
Matteo Berrettini was the defending champion from when the event was last held in 2019, but could not participate since he was still competing in the 2021 French Open at the beginning of the tournament.