Serena Williams was overpowered in a last-16 defeat to Maria Sakkari, while Japanese star Naomi Osaka won through at the Western & Southern Open.
Williams – the third seed – capitulated in a three-set loss to Sakkari at the WTA Premier tournament on Tuesday.
Fourth seed Osaka, though, had no such trouble against Dayana Yastremka as she reached the last eight in New York, where the event is being held instead of Cincinnati amid the coronavirus pandemic.
SAKKARI STUNS SERENA
Greek 13th seed Sakkari shocked 23-time grand slam champion Williams 5-7 7-6 (7-5) 6-1 under the New York lights.
Williams was two points away from serving out the match in the second set, but Sakkari rallied from 5-3 and a break down to prevail after two hours, 17 minutes.
Sakkari, having already claimed the scalp of American sensation Coco Gauff, will meet Johanna Konta for a spot in the semi-finals.
Konta defeated Vera Zvonareva 6-4 6-2.
OSAKA OVERPOWERS YASTREMSKA
Two-time grand slam champion Osaka was a class above in her 6-3 6-1 victory over 16th seed Yastremska.
Osaka hit ace eight aces and saved all five break points she faced en route to hr second quarter-final of the year.
Next up for Osaka is 12th seed Anett Kontaveit, who defeated Marie Bouzkova 6-3 6-3.
AZARENKA MASTERS CORNET
Two-time Australian Open champion Victoria Azarenka improved to 7-0 against Alize Cornet thanks to a 6-4 7-5 victory.
Former world number one and 2013 winner Azarenka progressed to her first quarter-final in over a year as Ons Jabeur awaits.
Jabeur was too good for Christina McHale 6-3 6-0.
As for fifth seed Aryna Sabalenka, she was upstaged 6-2 2-6 6-2 by American qualifier Jessica Pegula – who next faces Elise Mertens after the 15th seed eased past Veronika Kudermetova.