| 17th Jan - 06h20 |  Ivan Dodig
 Austin Krajicek | def. |  Miomir Kecmanovic
 Roman Safiullin | 3-6 6-1 6-2 |
| 18th Jan - 07h45 | Nikola Cacic
 Denys Molchanov | def. |  Ben McLachlan
Yoshihito Nishioka | 3-6 6-3 7-5 |
|  Simone Bolelli
Andrea Vavassori | def. |  Romain Arneodo
 Tristan-Samuel Weissborn | 3-6 6-3 7-6 |
| 16th Jan - 03h00 |  Nicolas Mahut
Edouard Roger-Vasselin | def. |  Francisco Cerundolo
Tomas Martin Etcheverry | 6-4 6-1 |
| 18th Jan - 06h55 |  Marcelo Arévalo
Mate Pavic | def. |  Constantin Frantzen
Hendrik Jebens | 7-6 6-3 |
|  N. Sriram Balaji
 Victor Vlad Cornea | def. | Matteo Arnaldi
Andrea Pellegrino | 6-3 6-4 |
| 18th Jan - 05h40 | Alexandre Muller
Sebastian Ofner | def. | Sebastian Baez
 Thiago Seyboth Wild | 6-4 6-2 |
| 17th Jan - 07h20 | Kevin Krawietz
Tim Pütz | def. | Marcos Giron
 Soon Woo Kwon | 6-2 6-0 |
|  Marcel Granollers-Pujol
Horacio Zeballos | def. | Evan King
 Roland Stadler | 6-3 7-6 |
| 19th Jan - 05h30 | Andreas Mies
 John-Patrick Smith | def. | Thanasi Kokkinakis
Alexei Popyrin | 6-7 6-4 6-4 |
| 18th Jan - 09h40 | Yannick Hanfmann
Dominik Koepfer | def. | Christopher Eubanks
Ben Shelton | 6-4 6-4 |
| 19th Jan - 01h10 | Rinky Hijikata
Jason Murray Kubler | def. | Laslo Djere
Christopher O'Connell | 6-2 6-4 |
| 17th Jan - 06h50 |  Lloyd Glasspool
 Jean-Julien Rojer | def. | Tallon Griekspoor
Bart Stevens | 7-6 6-2 |
| 18th Jan - 07h35 |  Andre Goransson
Albano Olivetti | def. | Blake Ellis
Andrew Harris | 6-1 7-5 |
| 19th Jan - 01h10 | Max Purcell
Jordan Thompson | def. | Alexander Erler
Lucas Miedler | 6-2 7-6 |
| 17th Jan - 04h25 | Hugo Nys
 Jan Zielinski | def. | James McCabe
Dane Sweeny | 6-7 7-5 6-2 |
| 17th Jan - 08h35 |  Santiago González
Neal Skupski | def. | Mackenzie McDonald
Botic van de Zandschulp | 7-6 6-1 |
| 18th Jan - 01h10 |  Francisco Cabral
Henry Patten | def. | Tristan Schoolkate
Adam Walton | 6-3 6-7 7-6 |
| 17th Jan - 06h00 |  Nicolás Barrientos
Rafael Matos | def. | Yuki Bhambri
Robin Haase | 1-6 7-6 7-6 |
| 19th Jan - 01h00 |  Ariel Behar
 Adam Pavlasek | def. | Jamie Murray
 Michael Venus | 6-2 6-4 |
| 17th Jan - 06h00 | Tomas Machac
 Zhizhen Zhang | def. |  Sander Gillé
Joran Vliegen | 6-4 7-5 |
| 18th Jan - 06h20 |  Marton Fucsovics
Fabian Marozsan | def. | Anirudh Chandrasekar
N. Vijay Sundar Prashanth | 6-3 6-4 |
| Daniel Altmaier
Miguel Ángel Reyes-Varela | def. |  Stefanos Tsitsipas
Petros Tsitsipas | 7-5 7-5 |
| 17th Jan - 09h55 | Rajeev Ram
Joe Salisbury | def. | Marcelo Melo
Matwe Middelkoop | 7-6 7-5 |
| 16th Jan - 02h30 | Máximo González
Andrés Molteni | def. | Pedro Cachin
Roberto Carballés Baena | 6-2 6-2 |
| 16th Jan - 04h00 | Nuno Borges
Aleksandar Vukic | def. |  Gonzalo Escobar
 Aleksandr Nedovyesov | 6-3 6-7 7-6 |
| 16th Jan - 01h00 | Quentin Halys
Adrian Mannarino | def. | Julian Cash
Robert Galloway | 5-7 7-5 6-1 |
| 17th Jan - 04h35 | Nathaniel Lammons
Jackson Withrow | def. | Jiri Lehecka
Petr Nouza | 3-6 7-5 6-4 |
| 18th Jan - 01h15 | Wesley Koolhof
Nikola Mektic | def. | Sadio Doumbia
Fabien Reboul | 7-6 2-6 6-3 |
| 18th Jan - 07h50 |  Harri Heliovaara
John Peers | def. | Alex Bolt
Luke Saville | 6-3 7-6 |
| 18th Jan - 01h10 | John Millman
Edward Winter | def. | Marcus Daniell
Marcelo Demoliner | 6-7 6-2 7-6 |
| 18th Jan - 06h20 | Rohan Bopanna
Matthew Ebden | def. | James Duckworth
Marc Polmans | 7-6 4-6 7-6 |
Andy Ram