23:50 CET - One of tennis' great entertainers, Gael Monfils (36) is through thanks to a 7-5, 6-4 victory over Alex De Minaur (24). Hubert Hurkacz (26) has also advanced.
23:14 CET - Stefanos Tsitsipas (25) is the next through in Cincinnati, defeating Ben Shelton (20) 7-6, 7-6.
Elsewhere, there were wins for French Open finalist Karolina Muchova (26) and Qinwen Zheng (20).
22:34 CET - Eighth seed Maria Sakkari (28) is through to the next round, advancing past Sorana Cirstea (33) 2-6, 6-3, 7-5.
Meanwhile, here is our WTA Flashmoment of the day.
21:53 CET - One of the bigger shocks of the day sees Max Purcell (25) defeat Casper Ruud (24) 6-4, 3-6, 6-4.
21:26 CET - As play continues in Cincinnati, here is our ATP Flashmoment of the day.
21:23 CET - Iga Swiatek (21), to no surprise, has cruised into the next round after a 6-1, 6-0 victory over Danielle Collins (29).
20:57 CET - More results in from the States as Dusan Lajovic (33) has upset last week's Canadian Open champion Jannik Sinner (21) in straight sets, winning the game 6-4, 7-6 in 125 minutes.
Home favourite Taylor Fritz (25) had no such problems, seeing off Lorenzo Sonego (28) 6-4, 7-6.
19:51 CET - Jessica Pegula (29) has continued her fine form with a nervy 6-7, 6-2, 6-3 victory over Martina Trevisan (29). Elsewhere, Wimbledon champion Marketa Vondrousova (24) is going well on the hard court too, beating Anastasia Potapova (27) 6-4, 6-2.
19:29 CET - Alex Zverev (26) has his second win in Cincinnati after seeing off Japan's Yoshihito Nishioka (27) in straight sets, winning their encounter 7-5, 6-4.
18:31 CET - Daniil Medvedev (27) cruised past Lorenzo Musetti (21), defeating the Italian 6-3, 6-2. Fellow Russian Daria Kasatkina (26) also had little issue, dismantling Varvara Gracheva (23) 6-3, 6-1.
17:14 CET - Play is underway in Cincinnati, with Montreal champion Jessica Pegula (29) currently on court. Daniil Medvedev (27) and Alexander Zverev (26) are also aiming to reach the next round.
After his first Masters triumph in Toronto last week, Jannik Sinner (22) is in action a little later, while Iga Swiatek (22) will be looking to bounce back after defeat to Pegula in Canada.
8:05 CET - Carlos Alcaraz (20) managed yet another tough victory as he barely got past Jordan Thompson (29) in Cincinnati, needing three sets to seal the deal 7-5, 4-6, 6-3.
5:30 CET - As we begin our day world number one Carlos Alcaraz has just won his first set in the opening round of the Cincinnati Open against Jordan Thompson 7-5. Alex de Minaur fought hard to get past JJ Wolff, winning after three sets 6-0, 3-6, 6-1.
Felix Auger Aliassime was on the wrong end of an upset as Frenchman Adrien Mannarino triumphed 6-4, 6-4.
More top seeds will be playing this afternoon as Daniil Medvedev takes on Lorenzo Musetti, Casper Ruud faces Max Purcell, Jannik Sinner, Stefanos Tsitsipas, Taylor Fritz, and Hubert Hurkacz will also be taking to court.
Meanwhile, Sloane Stephens surprisingly managed to take out world number six Caroline Garcia after a two-and-a-half-hour contest. The American was victorious 4-6, 6-4, 6-4.
Another unexpected result was Liudmila Samsonova's early exit at the hands of Linda Noskova, 2-6, 6-3, 6-1.
World number one Iga Swiatek takes on Danielle Collins later on in the day, Jessica Pegula clashes with Martina Trevisan while Maria Sakkari and Elena Rybakina's matches follow in the evening.