| Singles | |
|---|---|
| 2021 Internazionali di Tennis Città di Forlì | |
| Champion |  Mats Moraing |
| Runner-up |  Quentin Halys |
| Score | 3–6, 6–1, 7–5 |
Lorenzo Musetti was the defending champion [1] but chose not to defend his title.
Mats Moraing won the title after defeating Quentin Halys 3–6, 6–1, 7–5 in the final.
Tallon Griekspoor (first round)
Alessandro Giannessi (first round) Paolo Lorenzi (first round)
Steven Diez (quarterfinals)
Cem İlkel (first round) Robin Haase (first round)
Tomás Martín Etcheverry (semifinals) Quentin Halys (final)| Semifinals | Final | ||||||||||||
| 8 | Quentin Halys | 77 | 6 | ||||||||||
 Gastão Elias | 64 | 4 | |||||||||||
| 8 | Quentin Halys | 6 | 1 | 5 | |||||||||
| Mats Moraing | 3 | 6 | 7 | ||||||||||
| 7 | Tomás Martín Etcheverry | 3 | 5 | ||||||||||
| Mats Moraing | 6 | 7 | |||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 1 | T Griekspoor | 6 | 1 | 5 | |||||||||||||||||||||||
| Q | F Forti | 4 | 6 | 7 | Q | F Forti | 6 | 6 | |||||||||||||||||||
| Q | Lucas Gerch | 78 | 3 | 6 | Q | L Gerch | 4 | 4 | |||||||||||||||||||
| Q | TA Tirante | 66 | 6 | 3 | Q | F Forti | 5 | 3 | |||||||||||||||||||
| F Baldi | 3 | 5 | 8 | Q Halys | 7 | 6 | |||||||||||||||||||||
 E Benchetrit | 6 | 7 | E Benchetrit | 4 | 5 | ||||||||||||||||||||||
| J Lenz | 3 | 3 | 8 | Q Halys | 6 | 7 | |||||||||||||||||||||
| 8 | Q Halys | 6 | 6 | 8 | Q Halys | 77 | 6 | ||||||||||||||||||||
| 3 | P Lorenzi | 3 | 4 | G Elias | 64 | 4 | |||||||||||||||||||||
| Alt | R Brancaccio | 6 | 6 | Alt | R Brancaccio | 5 | 6 | 6 | |||||||||||||||||||
 D Ajduković | 77 | 5 | 77 | D Ajduković | 7 | 4 | 3 | ||||||||||||||||||||
| WC | F Passaro | 62 | 7 | 64 | Alt | R Brancaccio | 2 | 3 | |||||||||||||||||||
| G Elias | 6 | 6 | G Elias | 6 | 6 | ||||||||||||||||||||||
| PR | V Galović | 3 | 2 | G Elias | 6 | 79 | |||||||||||||||||||||
| Alt |  O Luz | 7 | 3 | 7 | Alt | O Luz | 4 | 67 | |||||||||||||||||||
| 5 | C İlkel | 5 | 6 | 5 | |||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 7 | TM Etcheverry | 6 | 6 | ||||||||||||||||||||||||
 M Jaziri | 4 | 2 | 7 | TM Etcheverry | 6 | 4 | 6 | ||||||||||||||||||||
| WC | F Cobolli | 6 | 7 | WC | F Cobolli | 4 | 6 | 2 | |||||||||||||||||||
| G Zeppieri | 0 | 5 | 7 | TM Etcheverry | 4 | 6 | 6 | ||||||||||||||||||||
| Q | S Fanselow | 2 | 2 | 4 | S Diez | 6 | 3 | 2 | |||||||||||||||||||
| C Ugo Carabelli | 6 | 6 | C Ugo Carabelli | 2 | 69 | ||||||||||||||||||||||
| A Arnaboldi | 0r | 4 | S Diez | 6 | 711 | ||||||||||||||||||||||
| 4 | S Diez | 5 | 7 | TM Etcheverry | 3 | 5 | |||||||||||||||||||||
| 6 | R Haase | 3 | 1 | M Moraing | 6 | 7 | |||||||||||||||||||||
| M Moraing | 6 | 6 | M Moraing | 3 | 6 | 6 | |||||||||||||||||||||
| I Sijsling | 6 | 77 | I Sijsling | 6 | 4 | 2 | |||||||||||||||||||||
| A Pellegrino | 2 | 65 | M Moraing | 6 | 6 | ||||||||||||||||||||||
| P Cachin | 4 | 6 | 6 | WC | J Berrettini | 3 | 4 | ||||||||||||||||||||
| H Grenier | 6 | 4 | 3 | P Cachin | 64 | 77 | 4 | ||||||||||||||||||||
| WC | J Berrettini | 6 | 77 | WC | J Berrettini | 77 | 64 | 6 | |||||||||||||||||||
| 2 | A Giannessi | 1 | 60 | ||||||||||||||||||||||||
Gianluigi Quinzi was the defending champion, but was no longer eligible to compete in junior tennis, and thus could not defend his title.
Borna Ćorić was the defending champion, having won the event in 2013, but elevated to Men's Singles instead as a qualifier.
Ernests Gulbis was the defending champion, but lost to Dominic Thiem in the quarterfinals.
Thiem went on to win his first ATP title, defeating Leonardo Mayer in the final, 6–7(8–10), 7–5, 7–6(7–2).
John Millman was the defending champion but chose not to defend his title.
Pierre-Hugues Herbert was the defending champion but withdrew before the tournament began.
Jordan Thompson was the defending champion but lost in the quarterfinals to Quentin Halys.
Nick Kyrgios was the defending champion, but withdrew before the tournament began.
Sam Querrey defeated Thanasi Kokkinakis in the final, 6–3, 3–6, 6–2 to win the singles tennis title at the 2017 Los Cabos Open. It was his ninth ATP Tour singles title.
Andy Murray was the defending champion, but could not participate this year as he was recovering from hip surgery.
Hiroki Moriya was the defending champion but chose not to defend his title.
Malek Jaziri was the defending champion but chose not to defend his title.
Dominic Thiem was the defending champion, but he chose not to defend his title this year.
Steve Johnson was the defending champion, but lost in the first round to Christopher Eubanks.
Alexander Zverev defeated top seed Stefanos Tsitsipas in the final, 6–4, 7–6(7–3) to win the men's singles tennis title at the 2021 Mexican Open.
Jack Draper was the defending champion but lost in the first round to Borna Gojo.
Radu Albot was the defending champion but lost in the second round to Antoine Escoffier.
Zizou Bergs was the defending champion but lost in the quarterfinals to Quentin Halys.
Lucas Pouille was the defending champion but lost in the first round to Martín Cuevas.
Lorenzo Sonego defeated Alexander Bublik in the final, 7–6(7–3), 6–2 to win the singles tennis title at the 2022 Moselle Open.
Oscar Otte was the defending champion but chose not to defend his title.