Aryna Sabalenka and Coco Gauff through at swealtering Cincinnati Masters

First seed Sabalenka powered through Talia Gibson and the heat for a 6-2, 7-6(2) win in one hour and 52 minutes. Temperatures reached 33C with high humidity, making conditions exceptionally difficult for the players. 

Sabalanka was forced to work hard as she let slip no fewer than five match points on her way to a second-set tiebreak. The world number one avoided going the distance largely through her ball-striking. Despite the wind, she carved out 30 winners, including 13 aces.

"Right now, I'm just super tired, it was super hot," the Belarusian said in her on-court interview.

"I hope you guys stay hydrated. It's really crazy weather. That was a tricky end of the match, and I feel she pulled out a really strong level at the very end. My energy really dropped in that last game, which was very awkward.

"I'm happy that even though she brought me back, I stayed calm and was able to pull out really great tennis in the tiebreak."

Meanwhile, fourth seed Coco Gauff recovered from a set down to defeat Liudmila Samsonova 2-6, 6-4, 6-1.

After Samsonova won the first set, Gauff earned a critical break in the tenth game of the second set to force a decider. The 2023 champion dominated the third set, winning the final five games to complete the comeback in a touch over two gruelling hours.

Elsewhere, eighth seed Elina Svitolina needed three sets to get past Tereza Valentova 3-6, 7-6(5), 6-0 to advance.

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