NEW YORK — So about that inflamed right shoulder that was supposed to hinder Serena Williams at the U.S. Open as she seeks a record 23rd major title: It sure seems to be just fine.
"Definitely feels solid," Williams said.
Not sure? There's plenty of evidence. No need to take her word — or her coach's — for it.
Look at the way Williams beat 47th-ranked Johanna Larsson 6-1, 6-1 on Saturday to reach the fourth round at Flushing Meadows and collect the 307th Grand Slam match victory of her career, surpassing Martina Navratilova for most by a woman in the Open era and equaling Roger Federer for most by anyone since 1968.
Williams reached 121 mph on a serve. She had a half-dozen aces, bringing her total this week to 31. She faced only one break point — her first of the tournament — and saved it. She smacked seven return winners. She compiled a 24-5 total edge in winners.
"Tennis-wise, I think it was very satisfying in all aspects. It's not perfect, of course," said her coach, Patrick Mouratoglou. "But for someone who didn't play much matches in the last two months, I think she's competitive."
Now there's an understatement.
"There is no pain. Maybe she feels a little. I don't know; I'm not in her shoulder. But I see she plays normal. She serves normal. At practice, she serves the quantity that we usually do, full power," Mouratoglou said. "So I don't see any problem. And she doesn't even talk about it. I know it's under control now."
That sounds like bad news for upcoming opponents, starting with 52nd-ranked Yaroslava Shvedova, who advanced to the round of 16 in New York for the first time by beating Zhang Shuai 6-2, 7-5.
Monday's other fourth-round women's matchups will be Williams' older sister Venus vs. No. 10 Karolina Pliskova, No. 5 Simona Halep vs. No. 11 Carla Suarez Navarro, and No. 4 Agnieszka Radwanska vs. Ana Konjuh. Venus Williams advanced comfortably Saturday night by beating No. 26 Laura Siegemund 6-1, 6-2. In that half of the draw, only the players with the last name Williams have won a Grand Slam title; the sisters could meet in the semifinals a year after Serena eliminated Venus in the quarters.
Two past men's champions, Andy Murray and Juan Martin del Potro, moved into the fourth round.
Murray, who won the 2012 U.S. Open, had trouble in each of the first two sets, but eventually became more patient during baseline exchanges and took control for a 7-6 (4), 5-7, 6-2, 6-3 victory over Paolo Lorenzi. Murray joins Kyle Edmund — who won Friday to set up a match against No. 1 Novak Djokovic — to give Britain two men in the round of 16 at the American Grand Slam tournament for the first time since 1966, when it was known as the U.S. Championships.
A third British man, Dan Evans, came within a point of also making the fourth round but failed to complete what would have been a significant upset, fading in a 4-6, 6-3, 6-7 (6), 7-6 (8), 6-2 loss to No. 3 Stan Wawrinka. Evans held a match point at 6-5 in the fourth-set tiebreaker, but Wawrinka erased it, then took that set and raced to a 4-0 lead in the fifth.
Wawrinka next faces 63rd-ranked Illya Marchenko, who advanced when No. 14 Nick Kyrgios quit because of injury while trailing two sets to one.
There's only one American man left: Jack Sock, who faces No. 9 Jo-Wilfried Tsonga on Sunday. That's because 19-year-old qualifier Jared Donaldson's run ended with a straight-set loss to 37-year-old Ivo Karlovic, the oldest man to reach the fourth round in New York since Jimmy Connors was 39 in 1991. Karlovic plays No. 6 Kei Nishikori next.
Del Potro's resurgence continued with a 7-6 (3), 6-2, 6-3 victory over No. 11 David Ferrer. The 2009 champion in New York missed 2 1/2 years' worth of major tournaments because of three operations on his left wrist, and he's ranked only 142nd, which is why he needed a wild-card invitation to get into the field.
Williams is 4-0 against Shvedova, who is best known for the first "golden set" in the Open era, which began in 1968: She won all 24 points of the first set against Sara Errani at Wimbledon in 2012.
"She's dangerous," Mouratoglou said. "But I think Serena is even more dangerous."
Larsson would probably agree.
"You're out there, you're trying to find ways to win," Larsson said, "but sometimes, it's just not happening."
Mouratoglou said Williams' shoulder began bothering her a day or two after Wimbledon, where she teamed with Venus to win doubles and tied Steffi Graf's Open-era record with Grand Slam singles title No. 22.
This was Williams' first daytime match of the U.S. Open, so she debuted a new outfit — a white dress accessorized with neon pink compression wraps on her arms, which she called "my 'Wonder Woman' sleeves."
"I feel this design, in particular, really is kind of like a superhero design," Williams said. "Like a really powerful, strong character that is strong, but yet isn't afraid to be soft at the same time."
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