From boardroom chic to battling win, Osaka reaches US Open last 16

NEW YORK, Sept 5 : Naomi Osaka continued to impress with her style and staying power at the U.S. Open on Saturday as the Japanese 13th seed shrugged off a late Achilles problem to beat Belgian Elise Mertens 6-3 3-6 7-5 and reach the fourth round.

For her latest eye-catching walk-on look, the four-times major champion blended boardroom and locker-room aesthetics in a grey checked blazer-hoodie and wide-leg pants, putting a tailored twist on traditional pre-match attire.

She looked on course for a business-like win after the first set but was dragged into a battle in the third, where she had to fight through the Achilles niggle to advance.

"I wouldn't say it's a huge injury," Osaka told reporters. "I'd say it's this ongoing problem that I've had since the grass season.

"I don't know why it hasn't gone away. I feel I've done a lot of things in order to make it better, but maybe the time off wasn't enough. I'm not really sure what the reason is, but the medical timeout was to address that.

"You know, she massaged my leg and stuff, so that seemed to help, and gave me Tylenol."

The 28-year-old, a two-times champion at Flushing Meadows, reeled off three games in succession to take a 4-1 lead in the first set under the lights of Louis Armstrong Stadium, clinching it with a battling hold thanks to a string of booming serves.

Osaka pushed the 23rd seed hard at the start of the next set with some heavy hitting from the baseline before pouncing with a break in the third game, only to surrender the lead by dropping the next two games.

"Honestly, I can't believe I won this match," Osaka said on court after sealing victory, thanking the crowd for the energy they provided.

"There was a certain point where I put my heart on the court and kept