Ashleigh Barty edged closer to a return to the top WTA ranking, reaching the WTA semi-finals as current number one Naomi Osaka retired with a knee injury.
Barty, the Australian top seed, on Friday engineered her second comeback in as many days, overhauling Maria Sakkari 5-7, 6-2, 6-0.
But the US Open alarm bells were ringing for Osaka less than two weeks before the start of her title defense at Flushing Meadows after a left knee injury saw her retire against Sofia Kenin -- sending the American into the semis with a 6-4, 1-6, 2-0 victory.
Men's top seed Novak Djokovic also had the trainer on during his 7-6 (7/2), 6-1 victory over Lucas Pouille, but hoped discomfort in his right elbow wouldn't linger.
"I managed to finish the match, there was a little bit of tightness in there," Djokovic said.
"Hopefully all will be fine for tomorrow."
"If there is a 1 percent chance of me not playing it, that's what's concerning me."
"She served amazing. She aced me almost every time I had a break point."
- No. 1 not Barty's focus -
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