Djokovic in action as Osaka battles into US Open last 16

New York (AFP) –


Novak Djokovic continues his bid for an 18th Grand Slam at the US Open on Friday after Naomi Osaka labored to a three-sets win to move into the last 16.

World number one Djokovic goes up against 28th seed Jan-Lennard Struff of Germany in the first evening match on day five at Arthur Ashe Stadium.

In early matches on Friday, two-time Grand Slam winner Osaka required three sets and 2hr 33 min to dislodge 18-year-old Ukrainian Marta Kostyuk.

The Japanese fourth seed, who threw her racquet in frustration after losing the second set on tie-break, prevailed 6-3, 6-7 (4/7), 6-2 against the world number 137.

"I just felt like I had so many points that I didn't capitalise on. I think when I went up, I became a bit passive and then she came in because she has no fear," said Osaka, 22.

Her experience came to the fore in the deciding set as she held her serve and broke Kostyuk twice to set up a match against either 14th seed Anett Kontavelt of Estonia or Poland's Magda Linette of Poland for a place in the quarter-finals.

"It was probably experience. I know she's very young and I think I have (played) more matches that are like this," Osaka said.

Elsewhere, eighth seed Petra Martic of Croatia swept aside unseeded Russian Varvara Gracheva 6-3, 6-3.

Martic will play Yulia Putintseva of Kazakhstan in the last 16 after the 23rd seed powered past Vera Lapko of Belarus 6-3, 6-3.

Germany's 17th seed Angelique Kerber also progressed to the fourth round, making light work of American Ann Li 6-3, 6-4.

Kerber, the 2016 US Open, will go up against Jennifer Brady for a quarter-final spot after the American 28th seed knocked out France's Caroline Garcia 6-3, 6-3. Garcia had provided the biggest upset of the tournament on Wednesday when she eliminated top seed Karolina Pliskova.

In the men's draw, seventh seed David Goffin brushed aside Serbia's 26th seed Filip Krajinovic 6-1, 7-6 (7/5), 6-4.

Djokovic is looking to close the gap on Roger Federer and Rafael Nadal, both absent from the tournament, in the race for the all-time men's Slam singles title record, at the US National Tennis Center.

Djokovic is on 17, with Nadal on 19 and Federer on 20.

Djokovic is 4-0 against Struff and defeated him in four sets in round one on the way to winning the Australian Open earlier this year.

Also in the men's competition Friday, fourth seed Stefanos Tsitsipas plays 27th seed Borna Coric of Croatia for a spot in the fourth round.

At Louis Armstrong Stadium, fifth seed Alexander Zverev takes on Adrian Mannarino, the 32nd seed from France.

And in the women's draw, sixth seed Petra Kvitova of the Czech Republic is takes on 63rd-ranked American Jessica Pegula.