| Singles | |
|---|---|
| 2023 Chicago Men's Challenger | |
| 2022 Champion |  Roman Safiullin |
Roman Safiullin was the defending champion [1] but chose not to defend his title.
| Singles | |
|---|---|
| 2023 Chicago Men's Challenger | |
| 2022 Champion | Roman Safiullin |
Roman Safiullin was the defending champion [1] but chose not to defend his title.
James Duckworth (withdrew)
Aleksandar Kovacevic (second round)
Emilio Gómez (first round)
Shang Juncheng 
Altuğ Çelikbilek (first round)
Alexis Galarneau (first round)
Giovanni Mpetshi Perricard (semifinals) Steve Johnson (first round)| Semifinals | Final | ||||||||||||
 Yuta Shimizu | 77 | 77 | |||||||||||
| 7 | Giovanni Mpetshi Perricard | 65 | 65 | ||||||||||
| Yuta Shimizu | |||||||||||||
| 4 | Shang Juncheng | 6 | 5 | 2 | |||||||||
| Alex Michelsen | 4 | 7 | 2 | ||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| LL | E Zhu | 2 | 4 | ||||||||||||||||||||||||
| Y Shimizu | 6 | 6 | Y Shimizu | 6 | 5 | 6 | |||||||||||||||||||||
| Q |  Y-s Chung | 6 | 6 | Q | Y-s Chung | 3 | 7 | 3 | |||||||||||||||||||
 A Shelbayh | 3 | 4 | Y Shimizu | 6 | 7 | ||||||||||||||||||||||
| Alt |  J Jung | 7 | 6 | Alt | J Jung | 2 | 5 | ||||||||||||||||||||
| Q | B Tomic | 5 | 3 | Alt | J Jung | 3 | 77 | 6 | |||||||||||||||||||
| N Basavareddy | 6 | 2 | 6 | N Basavareddy | 6 | 65 | 2 | ||||||||||||||||||||
| 8 | S Johnson | 3 | 6 | 4 | Y Shimizu | 77 | 77 | ||||||||||||||||||||
| 3 | E Gómez | 2 | 1 | 7 | G Mpetshi Perricard | 65 | 65 | ||||||||||||||||||||
| Alt | Y Uchiyama | 6 | 6 | Alt | Y Uchiyama | 6 | 2 | 2 | |||||||||||||||||||
 M Lajal | 6 | 6 | M Lajal | 4 | 6 | 6 | |||||||||||||||||||||
| Q | O Jasika | 1 | 4 | M Lajal | 63 | 6 | 66 | ||||||||||||||||||||
| WC | E Spizzirri | 2 | 2 | 7 | G Mpetshi Perricard | 77 | 4 | 78 | |||||||||||||||||||
| A Walton | 6 | 6 | A Walton | 63 | 4 | ||||||||||||||||||||||
| T Sandgren | 4 | 4 | 7 | G Mpetshi Perricard | 77 | 6 | |||||||||||||||||||||
| 7 | G Mpetshi Perricard | 6 | 6 | ||||||||||||||||||||||||
| First round | Second round | Quarterfinals | Semifinals | ||||||||||||||||||||||||
| 5 | A Çelikbilek | 4 | 62 | ||||||||||||||||||||||||
| Q | T Schoolkate | 6 | 77 | Q | T Schoolkate | 6 | 3 | 2 | |||||||||||||||||||
| Q |  E Escobedo | 66 | 6 | 4 | WC | E Quinn | 4 | 6 | 6 | ||||||||||||||||||
| WC | E Quinn | 78 | 0 | 6 | WC | E Quinn | 5 | 1 | |||||||||||||||||||
| D Sweeny | 4 | 4 | 4 | J Shang | 7 | 6 | |||||||||||||||||||||
| Q |  I Marchenko | 6 | 6 | Q | I Marchenko | 5 | 3 | ||||||||||||||||||||
| SE |  M Kukushkin | 65 | 2r | 4 | J Shang | 7 | 6 | ||||||||||||||||||||
| 4 | J Shang | 77 | 3 | 4 | J Shang | 6 | 5 | 2 | |||||||||||||||||||
| 6 | A Galarneau | 63 | 1 | A Michelsen | 4 | 7 | 2 | ||||||||||||||||||||
| WC | K Nishikori | 77 | 6 | WC | K Nishikori | 77 | 6 | ||||||||||||||||||||
| Alt |  S Mansouri | 3 | 6 | 6 | Alt | S Mansouri | 61 | 4 | |||||||||||||||||||
| Alt | J McCabe | 6 | 4 | 4 | WC | K Nishikori | 613 | 6 | 1 | ||||||||||||||||||
| L Tu | 63 | 77 | 65 | A Michelsen | 715 | 3 | 6 | ||||||||||||||||||||
| A Michelsen | 77 | 65 | 77 | A Michelsen | 6 | 6 | |||||||||||||||||||||
| B Zhukayev | 3 | 4 | 2 | A Kovacevic | 4 | 2 | |||||||||||||||||||||
| 2 | A Kovacevic | 6 | 6 | ||||||||||||||||||||||||
Filip Peliwo was the champion the previous year, but could not defend his title as he was no longer eligible to compete in junior tennis.
Borna Ćorić won the title, defeating Thanasi Kokkinakis in the final, 3–6, 6–3, 6–1.
Borna Ćorić was the defending champion, having won the event in 2013, but elevated to Men's Singles instead as a qualifier.
Roman Safiullin defeated Hong Seong-chan in the final, 7–5, 7–6(7–2) to win the boys' singles tennis title at the 2015 Australian Open.
Toshihide Matsui and Vishnu Vardhan were the defending champions but only Matsui chose to defend his title, partnering Saketh Myneni. Matsui lost in the first round to Ivan Gakhov and Roman Safiullin.
Luca Vanni was the defending champion but chose not to defend his title.
Ugo Humbert was the defending champion but chose not to defend his title.
Roman Safiullin was the defending champion but chose not to defend his title.
Pavel Kotov and Roman Safiullin were the defending champions but chose not to defend their title.
Zizou Bergs was the defending champion but lost in the second round to Kacper Żuk.
Evgeny Donskoy was the defending champion but chose not to defend his title.
Brandon Nakashima was the defending champion but chose not to participate.
Alexander Bublik defeated Alexander Zverev in the final, 6–4, 6–3 to win the singles title at the 2022 Open Sud de France. It was his maiden ATP Tour title.
Andrey Rublev defeated Félix Auger-Aliassime in the final, 7–5, 7–6(7–4) to win the singles title at the 2022 Open 13 Provence.
Zizou Bergs was the defending champion but lost in the quarterfinals to Quentin Halys.
Kamil Majchrzak was the defending champion but chose not to defend his title.
Andrey Rublev defeated Novak Djokovic in the final, 6–2, 6–7(4–7), 6–0 to win the singles tennis title at the 2022 Serbia Open.
Andrey Kuznetsov was the defending champion but chose not to defend his title.
Jason Kubler was the defending champion but chose not to defend his title.
Félix Auger-Aliassime defeated Holger Rune in the final, 6–3, 7–5 to win the singles tennis title at the 2022 Swiss Indoors. It was his third title in as many weeks and fourth career ATP Tour singles title overall.
Novak Djokovic defeated Sebastian Korda in the final, 6–7(8–10), 7–6(7–3), 6–4 to win the men's singles title at the 2023 Adelaide International 1. He saved a championship point en route to his 92nd ATP Tour singles title, equaling Rafael Nadal's tally for the fourth-most men's singles titles in the Open Era.