Iga Swiatek and Coco Gauff were both back in action on Monday.
Both players, who are competing in their first Olympics, dropped just two total games and continue to look like firm favorites to reach the final round.
That is, unless Danielle Collins has something to say about it.
The No. 8 seed, who has a blistering forehand, defeated Caroline Wozniacki in a three-set thriller.
Collins, who plans to retire after the 2024 season, is among the top five favorites to win the Olympic gold and will likely face Swiatek in the quarterfinal.