Tokyo (AFP) - Serbia's Aleksandra Krunic made further progress at the Japan Women's Open on Wednesday by eliminating seventh seed Alison Riske, a day after ushering local favourite Kimiko Date into retirement.

The world No. 67, who conquered her emotions to whitewash 46-year-old Date on Tuesday, powered to a 6-3, 6-4 win over American Riske in sweltering conditions to reach the quarter-finals.

Third seed Elise Mertens also booked her place in the last eight, the Belgian overpowering Poland's Magda Linette 6-1, 7-5.

In the first-round matches, Kurumi Nara upset sixth seed Naomi Osaka 6-3, 6-0 as the next generation of Japanese tennis players took centre stage after Date's tearful exit.

Osaka, who reached the third round of the US Open earlier this month after stunning then defending champion Angelique Kerber of Germany, left her game in the locker room as she came out inexplicably flat.

"I felt really nervous," shrugged Osaka. "I didn't cope with the pressure and I just think emotionally I wasn't really there."

Australia's former 2011 US Open winner Samantha Stosur was bundled out by Spain's Sara Sorribes, who came from a set down to beat the fifth seed 3-6, 7-5, 6-1.

Second seed Zhang Shuai safely progressed to the last 16 by thrashing Dutchwoman Richel Hogenkamp 6-3, 6-3 as Tokyo organisers looked to clear a backlog of matches caused by rain on Tuesday.