One champion saw her US Open outlook come into question and a slew of players continued to impress heading into the weekend. These are the Top 5 photos from Cincinnati.
1. World No. 1 Naomi Osaka was locked in a tight battle with Sofia Kenin during their quarterfinal. Osaka had won six of eight games before coming down on her leg following her service motion and felt pain around her left knee. After playing two points, ultimately getting broken to fall behind 2-0 to start the third set, Osaka retired from the match.
"It sucks, especially since I didn't want to get injured this close to the [US] Open," Osaka said. "And now I'm kind of worried a little bit."
2. Richard Gasquet kept his impressive week going after posting a 7-6 (2), 3-6, 6-2 victory over No. 11 seed Roberto Bautista Agut. This marks the Frenchman's first ATP Masters 1000 semifinal since 2013 and he will continue his quest for a first ATP Masters 1000 crown on Saturday against No. 16 seed David Goffin.
3. Two-time Grand Slam champion Svetlana Kuznetsova hit 30 winners to upset No.3 seed Karolina Pliskova 3-6, 7-6(2), 6-3. The Russian, who was down 6-3, 5-3, will take on French Open champion Ashleigh Barty on Saturday in her first Cincinnati semifinal appearance.
4. Daniil Medvedev ended the outstanding qualifying run of compatriot Andrey Rublev. In just 61 minutes, Medvedev posted a 6-2, 6-3 victory to advance to his second straight ATP Masters 1000 semifinal. The Russian is coming off final runs in Washington D.C. and Montreal, and is peaking just ahead of the season's final major tournament.
5. Ash Barty is on a quest to snatch world No. 1 back this week, as she rallied past Maria Sakkari, 5-7, 6-2, 6-0. If the Australian defeats Svetlana Kuznetsova in Saturday's semifinals, she will overtake Naomi Osaka at the top just in time for the US Open.