# 2023 Internazionali di Tennis Città di Trieste – Singles

Francesco Passaro was the defending champion but lost in the final to Hugo Gaston.
Gaston won the title after defeating Passaro 6–3, 5–7, 6–2 in the final.

## Seeds

* Fábián Marozsán (semifinals)
* Pedro Martínez (semifinals)
* Tomás Barrios Vera (first round)
* Hugo Gaston (champion)
* Alejandro Tabilo (withdrew)
* Francesco Passaro (final)
* Flavio Cobolli (second round)
* Zdeněk Kolář (second round)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final | Final |
| 1 | Fábián Marozsán | 6 | 5 | 2 | | | | | |
| 6 | Francesco Passaro | 3 | 7 | 6 | | | | | |
| 6 | Francesco Passaro | 3 | 7 | 6 | 6 | Francesco Passaro | 3 | 7 | 2 |
| | | | | | 4/SE | Hugo Gaston | 6 | 5 | 6 |
| 4/SE | Hugo Gaston | 6 | 3 | 6 | 4/SE | Hugo Gaston | 6 | 5 | 6 |
| 2 | Pedro Martínez | 3 | 6 | 2 | | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 1 | F Marozsán | 6 | 7$^7$ | | | | | | | | | | | | | | | | |
| LL | G Villanueva | 2 | 6$^3$ | | 1 | F Marozsán | 7$^7$ | 3 | 7 | | | | | | | | | | |
| Q | C Tabur | 4 | 7$^7$ | 3 | | M Gigante | 6$^4$ | 6 | 5 | | | | | | | | | | |
| | M Gigante | 6 | 6$^5$ | 6 | | | | | | 1 | F Marozsán | 6 | 6 | | | | | | |
| Alt | C-h Tseng | 6 | 6$^3$ | 6$^7$ | | | | | | WC | E Dalla Valle | 1 | 4 | | | | | | |
| WC | E Dalla Valle | 4 | 7$^7$ | 7$^9$ | WC | E Dalla Valle | 7$^7$ | 6 | | | | | | | | | | | |
| | A Pellegrino | 4 | 5 | | 7 | F Cobolli | 6$^5$ | 1 | | | | | | | | | | | |
| 7 | F Cobolli | 6 | 7 | | | | | | | | | | | | 1 | F Marozsán | 6 | 5 | 2 |
| 3 | T Barrios Vera | 5 | 2 | | | | | | | | | | | | 6 | F Passaro | 3 | 7 | 6 |
| | G Andreozzi | 7 | 6 | | | G Andreozzi | 6 | 7$^7$ | | | | | | | | | | | |
| Alt | M Bourgue | 4 | 2 | | | A Andreev | 3 | 6$^5$ | | | | | | | | | | | |
| | A Andreev | 6 | 6 | | | | | | | | G Andreozzi | 6 | 1 | 4 | | | | | |
| | D Prižmić | 6 | 6 | | | | | | | 6 | F Passaro | 3 | 6 | 6 | | | | | |
| | M Polmans | 4 | 2 | | | D Prižmić | 6 | 4 | 2 | | | | | | | | | | |
| | L Darderi | 4 | 4 | | 6 | F Passaro | 4 | 6 | 6 | | | | | | | | | | |
| 6 | F Passaro | 6 | 6 | | | | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| Q | K Jacquet | 6 | 7$^{11}$ | | | | | | | | | | | | | | | | |
| Q | C Taberner | 3 | 6$^9$ | | Q | K Jacquet | 6 | 6 | | | | | | | | | | | |
| | L Neumayer | 4 | 6 | 4 | | V Sachko | 3 | 4 | | | | | | | | | | | |
| | V Sachko | 6 | 4 | 6 | | | | | | Q | K Jacquet | 6 | 4 | 4 | | | | | |
| | RA Burruchaga | 6 | 1 | 6 | | | | | | 4/SE | H Gaston | 4 | 6 | 6 | | | | | |
| LL | Andrey Chepelev | 2 | 6 | 4 | | RA Burruchaga | 3 | 6 | 0 | | | | | | | | | | |
| | S Caruso | 1 | 0 | | 4/SE | H Gaston | 6 | 4 | 6 | | | | | | | | | | |
| 4/SE | H Gaston | 6 | 6 | | | | | | | | | | | | 4/SE | H Gaston | 6 | 3 | 6 |
| 8 | Z Kolář | 7$^7$ | 2 | 6 | | | | | | | | | | | 2 | P Martínez | 3 | 6 | 2 |
| WC | Gabriele Piraino | 6$^5$ | 6 | 3 | 8 | Z Kolář | 6 | 6$^4$ | 6$^0$ | | | | | | | | | | |
| Q | S Napolitano | 6 | 6 | | Q | S Napolitano | 4 | 7$^7$ | 7$^7$ | | | | | | | | | | |
| | A Giannessi | 4 | 2 | | | | | | | Q | S Napolitano | 2 | 4 | | | | | | |
| Q | C Sánchez Jover | 5 | 6 | 6$^3$ | | | | | | 2 | P Martínez | 6 | 6 | | | | | | |
| WC | Marcello Serafini | 7 | 1 | 7$^7$ | WC | M Serafini | 3 | 5 | | | | | | | | | | | |
| Q | P Gojowczyk | 1 | 3 | | 2 | P Martínez | 6 | 7 | | | | | | | | | | | |
| 2 | P Martínez | 6 | 6 | | | | | | | | | | | | | | | | |