Marie Bouzkova moved into the second round of the Western & Southern Open on Tuesday, as No.11 seed Coco Gauff had to retire from their match after suffering a left ankle injury.

Gauff was leading 5-3, 30-15 when she turned her ankle. Gauff received treatment on the ankle but Bouzkova won the remaining games of the opening set. After dropping serve in the first game of the second set, Gauff called a stop to the match.

It is an unfortunate end to Gauff's Cincinnati campaign, which saw her week begin by claiming the WTA Doubles World No.1 ranking for the first time. Gauff, 18, is the second-youngest player to ever hold the top spot in the doubles rankings.

Despite the retirement ending, Bouzkova now has 14 wins in her last 16 matches (including qualifying wins in Cincinnati over the weekend). Already this summer, Bouzkova reached her first Grand Slam quarterfinal at Wimbledon and won her first WTA singles title in Prague.

Bouzkova will face another American, Alison Riske-Amritraj, in the second round. In their only prior meeting, Bouzkova beat Riske-Amritraj 6-2, 6-3 en route to the Wimbledon quarterfinals this summer.

Anett Kontaveit came back from a set and a double-break down to win on Tuesday.

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Later on Tuesday, No.2 seed Anett Kontaveit became the first competitor to reach the Round of 16 this week, earning a 3-6, 7-5, 6-4 rain-interrupted win over qualifier Tereza Martincova after two-and-a-half hours of play.

World No.71 Martincova led by a set and a double-break at 3-0 before Kontaveit stormed back, winning five of the last six games in the second set. An additional wrench was thrown into the works when an hour-long rain delay hit Cincinnati at 3-2 in the third set.

Upon resumption of play, Martincova went up a break at 4-3, but Kontaveit again fought back, converting her fourth break point of the next game to level the decider at 4-4. Kontaveit stayed sturdy and claimed a second consecutive break at 5-4 to seal the victory.

Caroline Garcia won her 23rd main-draw match since June on Tuesday night.

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Caroline Garcia, though, pulled off an upset to book her own spot in the Round of 16. The World No.35 from France ousted No.4 seed Maria Sakkari of Greece 7-6(2), 6-7(6), 6-1 in the 2-hour and 18-minute nightcap.

Former World No.4 Garcia has now won 23 main-draw matches since June -- more than any other player on tour during that timeframe. Her resurgent form includes title runs at Bad Homburg and Warsaw.

Highlights: Garcia d. Sakkari

On Tuesday night, there were only two service breaks total in the first two sets, but Garcia still nearly won in two tiebreak sets. However, the Frenchwoman let a 4-0 lead in the second-set tiebreak slip away, and Sakkari stole the second set without facing a match point.

Garcia, though, regrouped tremendously in the third set, taking aggressive stances on return and powering through the decider to reach the Cincinnati Round of 16 for the first time since 2018.

Shelby Rogers in action during her first-round win in Cincinnati on Tuesday.

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Also on Tuesday, Shelby Rogers moved into the second round, breezing past fellow American and 2020 Australian Open champion Sofia Kenin 6-2, 6-1.

Rogers and Kenin had not met since 2016, when they split their two meetings at ITF Challenger events. Over six years later, Rogers took the 2-1 lead in their rivalry with a 66-minute victory.

Rogers won a staggering 92 percent of her first-service points in Tuesday's match (23 of 25). Rogers, currently ranked at a career-high No.30, also fired nine aces and never faced a break point.

Cincinnati: Kontaveit survives Martincova from 6-3, 3-0 down