Lucia Bronzetti vs Tereza Valentova
(17:00 CET, Court 5)
Tereza Valentova is starting to make a name for herself, even though she is the fourth youngest player in the singles pool at this year's US Open. Thanks to her impressive performances, she has broken into the elite 100 of the rankings this year and also made her way to her second Grand Slam.
And given her style of play, outdoor hard courts are the ideal environment for her to continue her rise. The tough schedule of the last few days may be a problem for the young Czech, as she will enter the main event with only a day of rest after three rounds of qualifying.
Lucia Bronzetti had a very bad season on clay and grass. That's why she is trying to make up for the deficit on the hard court. Her run to the fourth round in Cincinnati, including scalps of Daria Kasatkina and Jelena Ostapenko, suggests a return to form.
The bookmakers favour Valentova probably because of the Italian's fluctuating performance, but it doesn't have to be clear-cut, as the Italian is 40 places higher in the rankings.
Follow the women's singles tournament at the US Open here.
Tallon Griekspoor vs Adrian Mannarino
(20:00 CET, Court 7)
Tallon Griekspoor, while enjoying the privileges of a seeded player, was hoping for an easier draw. He's not having an ideal season. He lost all three of his matches in America before the US Open and has had four setbacks in a row overall.
By contrast, French veteran Adrian Mannarino has been a joy to watch in recent months. He was only stopped in Cincinnati by Jannik Sinner, and he has also impressed in Toronto and on grass at Newport and Wimbledon. In the last three months, he has climbed more than 70 places back into the top 100.
Griekspoor has long struggled to be a clay court player, and the bulk of his victories have come on hard court; it's just that now his career success is countered by poor form. However, if the duel stretches to five sets, the younger Dutchman will have the better chance.
Novak Djokovic vs Learner Tien
(01:00 CET, Arthur Ashe Stadium)
Obviously, the most interesting duel of the first day will be marked by a clash of two generations. Learner Tien is a rising star and now a top 50 player. And so, despite his 24 Grand Slam trophies, Novak Djokovic (who is 19 years older) will not have it easy against the determined American.
Tien will probably be spurred on by the home support and the knowledge that he managed to outplay both Alexander Zverev and Daniil Medvedev this year.
Another complication for the Serb may be the fact that he has not played a single match since Wimbledon, while Tien has played three tournaments and has had nine matches on outdoor American concrete. So a seemingly straightforward match could turn into a huge upset...