04:00 CET - A pair of tiebreaks proves to be difference-maker between Mattia Bellucci and Damir Dzumhur as the Bosnian prevails 7-6 (7), 7-6 (5).
03:15 CET - Barbora Krejcikova needed three sets, but manages to move on in Cincinnati. She outlasts Alycia Parks 6-4, 4-6, 6-0 in a two-hour battle.
02:25 CET - Learner Tien is moving on in the Cincinnati Open. The world number 55 gets past Swiss qualifier Leandro Riedi 6-3, 6-4.
01:25 CET - Veronika Kudermetova gets the job done as she beats Suzan Lammens 6-1, 6-3 in just over an hour.
01:10 CET - It took two tiebreaks, but Roberto Bautista-Agut marches on in Cincinnati. The Spaniard defeats Daniel Altmeier 7-6 (5), 7-6 (1).
23:37 CET - Former world number three Maria Sakkari has moved into the second round with a 6-3, 3-6, 6-2 win over Kamila Rakhimova, and she'll be joined in that round by fellow victors Camila Osorio and Viktoriya Tomova.
22:59 CET - Another American is through, with world number 82 Ethan Quinn claiming an impressive 7-6, 6-4 win over Miomir Kecmanovic.
22:32 CET - Varvara Gracheva and Ella Seidel have both battled through with three-set wins over Katie Volynets and Polina Kudermetova.
21:53 CET - Former world number 12 Borna Coric is out, with the Croatian losing 6-3, 7-5 to qualifier Emilio Nava.
21:30 CET - 20-year-old Belgian talent Alexander Blockx has claimed his first ATP win, beating Marcos Giron 6-2, 3-6, 6-3. What a moment for the youngster!
21:00 CET - Danielle Collins has fallen at the first hurdle, with the 2021 quarter-finalist losing 6-4, 7-6 to Taylor Townsend.
20:46 CET - Australian pair Ajla Tomljanovic and Kimberly Birrell have both won in straight sets, while Lucia Bronzetti has won a gruelling battle against Lin Zhu that lasted almost four hours, prevailing 6-7, 6-2, 7-6 after saving a match point.
19:59 CET - Caroline Garcia has battled through in Cincinnati, recovering from a set down to defeat Sonay Kartal 5-7, 6-4, 6-3, while Rebecca Sramkova has also progressed courtesy of a 1-6, 6-4, 7-6(1) triumph over Caroline Dolehide.
19:04 CET - An all-American clash has been won by Tristan Boyer, who has beaten Brandon Holt 6-3, 7-6 in just under two hours, while Lucky Loser Luca Nardi has won 6-4, 7-6 against Thiago Agustin Tirante.
18:45 CET - In the first result of the day, Lulu Sun of New Zealand has beaten Croatian qualifier Antonia Ruzic 6-4, 6-4.
On the men's side, Japanese veteran Kei Nishikori has been beaten 7-5, 6-3 by world number 47 Camilo Ugo Carabelli.
17:15 CET - Play has now started for the day at the Cincinnati Open! Follow all the latest men's action here and the women's matches here.
14:00 CET - Good afternoon and welcome to our coverage of today's tennis at the Cincinnati Open!
Play gets underway in a few hours as Kei Nishikori, Caroline Garcia and Rebecca Sramkova take to the court at 17:00 CET.
Later on, two-time major champion Barbora Krejcikova begins her campaign against home favourite Alycia Parks, while rising American star Learner Tien takes on qualifier Leandro Riedi.
Check out the full men's schedule in Cincinnati here and the full women's draw here.