Serena wins all-Williams clash

Serena Williams turned her 30th career meeting with her sister Venus into a one-woman showcase, reaching the US Open fourth round with a 6-1, 6-2 victory.

Reluctantly rising to an occasion neither sister enjoys, Serena said she played her best match since she returned in March, more than six months after giving birth to daughter Olympia last September 1.

"I played much better tonight than I have since I started this journey on my way back," said Serena, although she wasn't sure she'd agree with Venus's assessment that it was the best match she'd ever played against her sister.

"I think it's by far the best match I ever played against her in forever," she said Friday.

"But I don't know about ever, ever." Either way, the scoreline equalled Serena's most lopsided victory over Venus, and took her head-to-head record against her sister to 18-12.

"She played so well, I never got to really even touch any balls," Venus said.

"I don't think I did a lot wrong. But she just did everything right."

"Obviously that level is definitely where she's going to want to stay during this whole tournament."

Serena will try to take the next step when she takes on Kaia Kanepi for a place in the quarter-finals.

The Estonian, who toppled world number one Simona Halep in the first round, defeated Sweden's Rebecca Peterson 6-3, 7-6 (7/3).

Defending champion Sloane Stephens, at No 3 the highest seed left in the draw after the exits of Halep and world number two Caroline Wozniacki, booked her fourth-round berth with a 6-3, 6-4 victory over former world number one Victoria Azarenka.

Up a break in the final set, Stephens had slipped behind 4-3 when a light shower prompted officials to close the Ashe Stadium for the first time this week.

Both players had a chance to leave the court and the break refreshed Stephens, who came back to win the last three games in the "super-cool" atmosphere of the closed stadium.

"It kind of felt like a night match with the lights on and everything," said Stephens, who said the break allowed her to "refocus".

"I played much better the last three games," she said.

"I competed. When things got tough, I just hung in there, battled as hard as I could, ran down every ball."

Stephens will face 15th-seeded Belgian Elise Mertens for a place in the quarters after Mertens beat Czech Barbora Strycova 6-3, 7-6 (7/4).

Seventh seeded Ukrainian Elina Svitolina beat China's Wang Qiang 6-4, 6-4 to set up a meeting with Latvian Anastasija Sevastova, a 4-6, 6-1, 6-2 winner over Russian Ekaterina Makarova.

Nadal in last 16

World number one and defending champion Rafael Nadal came back from a set and break down to defeat big-hitting Karen Khachanov 5-7, 7-5, 7-6 (9/7), 7-6 (7/3) and reach the US Open fourth round.

The top seeded Spaniard triumphed after an epic 4 hour 23 minute struggle on Arthur Ashe Stadium in a match where the 22-year-old Khachanov had served for a two sets to love lead in the 10th game of the second set and had a set point in the fourth-set tiebreaker on Friday.

Nadal, seeking a fourth US Open title and 18th major, will face Georgia's world number 37 Nikoloz Basilashvili for a place in the quarter-finals.

Basilashvili reached the last-16 of a Slam for the first time by seeing off Argentina's Guido Pella 6-3, 6-4, 1-6, 7-6 (7/4).

Meanwhile, South Africa's Kevin Anderson, who was runner-up to Nadal last year, outlasted Canadian teenager Denis Shapovalov 4-6, 6-3, 6-4, 4-6, 6-4 as the roof on the new Louis Armstrong Stadium was closed for the first time.

The fifth seed, runner-up to Novak Djokovic at Wimbledon, next faces ninth-seeded Austrian Dominic Thiem, who made the last 16 for the fourth time in five years with a 3-6, 6-3, 7-6 (7/5), 6-4 victory over American Taylor Fritz.

John Isner, the last American man standing, fired 34 aces, 85 winners and saved the three break points he faced in beating Serbia's Dusan Lajovic 7-6 (10/8), 6-7 (6/8), 6-3, 7-5.

He will face Milos Raonic who put out 2016 champion Stan Wawrinka 7-6 (8/6), 6-4, 6-3.

Croatian 20th seed Borna Coric made the last 16 of a Slam for the first time with a 6-3, 7-5, 6-2 victory over Russia's Daniil Medvedev.