NEW YORK • After 17 trips to Flushing Meadows and six US Open titles, Serena Williams did something on Thursday she had never done in the tennis calendar's final Major - win indoors.
With the new high-tech retractable roof over Arthur Ashe Stadium slammed shut because of persistent rain, Williams swept past fellow American Vania King 6-3, 6-3 to ease into the third round.
"It was a little different playing with Ashe closed but it still feels great," said Williams.
Indoors or outdoors, night or day, rain or shine, it has made little difference to Williams at the US Open. The 34-year-old has now racked up her 306th Grand Slam singles win, tying her with Martina Navratilova for the most ever for a woman.
"This one's kind of cool," she said of her latest milestone, "to win 306."
She fired 13 aces, with a total of 38 winners against 87th-ranked wildcard King, and said the troublesome right shoulder that has hindered her since Wimbledon was not a problem.
Grand Slam singles victories in Serena Williams' career since she turned professional in 1995 - a record.
Grand Slam singles win by Williams under the Arthur Ashe Stadium roof.
Williams arrived at Flushing Meadows with concerns swirling around a sore shoulder that hampered her at the Rio Olympics and forced her to pull out of the Cincinnati Open. But she put any doubts about her fitness to rest after cruising to victory.
"It's stable, I just got to keep it like that," she said of her right shoulder.
"It's two matches in and usually you want to be able to play seven matches. I definitely want to keep it as good as it can be."
She was cheered on by rap mogul Jay Z and his pop superstar wife Beyonce as she booked a meeting with 47th-ranked Swede Johanna Larsson today for a place in the last 16.
SHOULDERING THE LOAD
It's stable... it's two matches in and usually you want to be able to play seven matches. I definitely want to keep it as good as it can be.
SERENA WILLIAMS, on whether her recent shoulder injury is hampering her at the US Open.
Despite wrapping up the victory in just 65 minutes, Williams said there was plenty of room for improvement.
"I feel like I made a lot of errors," said the top seed, who made 28 unforced errors - 17 more than King.
"What really matters is I got the win. Hopefully I'll just get better."
By the time she opened the night session, the rain that prompted organisers to close the new roof had tailed off.
Fourth seed Agnieszka Radwanska of Poland survived an early onslaught from US Open debutante Naomi Broady to beat the Briton 7-6 (11-9), 6-3.
Fired-up fifth seed Simona Halep also advanced, downing Czech Lucie Safarova 6-3, 6-4 in a battle of former French Open finalists.
Venus Williams, the sixth seed whose seven Grand Slam titles include two at the US Open, coasted to the 70th US Open match win of her career. The 36-year-old beat Germany's Julia Goerges 6-2, 6-3.
The elder Williams, bedevilled by 63 unforced errors in a scrappy first-round win over Ukrainian Kateryna Kozlova, cut that to 17 in a crisp performance against the 64th-ranked German.
REUTERS, AGENCE FRANCE-PRESSE
US OPEN DAY 6
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