Coco Gauff's Cincinnati bid cut short after rolling ankle; Venus Williams falls to Karolina Pliskova

WATCH: Marie Bouzkova advances after Coco Gauff retires during their 2022 Cincinnati first round match

On Monday, Coco Gauff reached No. 1 in the WTA doubles rankings following her Toronto title run with Jessica Pegula. A day later, Gauff found her US Open singles preparation cut short when she rolled her left ankle in the first round of Cincinnati’s Western & Southern Open against Marie Bouzkova.

Serving for the first set at 5-3, 30-30, Gauff went down hard behind the baseline. She continued to play on, but the Czech worked her way back on the scoreboard to grab control. Treatment during a medical timeout proved fruitless in the end for this year’s Roland Garros runner-up.

Meanwhile, Bouzkova came into the contest with a pair of convincing qualifying wins over Aleksandra Krunic and Donna Vekic. Another American, Alison Riske, awaits in the second round.

Earlier, wild card Venus Williams also bowed out. The seven-time major singles champion held an early break led against Karolina Pliskova, before the 2016 champion surged and eventually pulled away for a 7-5, 6-1 victory.

“I just felt like, come on, physically I have to win this match. But I was actually close to losing the first set because she was really playing well,” 30-year-old Pliskova told press afterwards.

“The match was close to two hours, so the longer the match goes, the bigger chance should be for me. If I lose, then I'm doing something wrong.”

Shelby Rogers took an all-American encounter without much resistance, dismissing Sofia Kenin, 6-2, 6-1. Countrywoman Amanda Anisimova, who lost to Rogers in the quarterfinals of San Jose on August 5, seeks revenge Wednesday.

Buddies Taylor Fritz and Tommy Paul also moved forward in dominant fashion. Fritz brushed aside Sebastian Baez, 6-1, 6-1, while Paul eliminated compatriot Jenson Brooskby, 6-3, 6-2.