Wham-bam as Japan's Osaka roars into Tokyo quarters

Japan's Naomi Osaka pulverised Slovak Dominika Cibulkova 6-2, 6-1 to reach the Pan Pacific Open quarter-finals on Wednesday in her first match since her historic US Open triumph.

The 20-year-old, who stunned Serena Williams to become Japan's first grand slam singles champion earlier this month, fired down 10 aces in a fearsome display of wham-bam tennis in Tokyo.

Osaka came out firing and ripped a fizzing forehand down the line on the first point, the third seed powering away to close out the first set with a pair of thundering aces.

A dazed Cibulkova had no answer to Osaka's firepower as the world number seven wrapped up a comfortable victory with a ferocious cross-court backhand after just 59 minutes.

"I didn't really feel any pressure," said Osaka, who reached the Tokyo final in 2016.

"It was really difficult because she's such a great player but I just thought it was more fun.

"My serve was really good," added Japan's latest sporting celebrity.

"I'm just grateful to be able to ...