NEW YORK — Taylor Townsend charged into the fourth round of a Grand Slam tournament for the first time Saturday, beating Sorana Cirstea 7-5, 6-2 at the U.S. Open.

Two days after upsetting Wimbledon champion Simona Halep, Townsend stuck to her aggressive game plan, and repeatedly rushed the net to set up easy volleys and smashes.

“I just tried to do what I did in the last round and tried to get better,” Townsend said.

The 23-year-old Townsend’s victory came before defending champion Naomi Osaka ended 15-year-old Coco Gauff’s run, 6-3, 6-0.

Townsend came forward 75 times against Cirstea, amassing a 47-8 advantage in net points won. That style got her past Halep, the No. 4 seed, and never let Cirstea come back in a match that lasted less than 90 minutes.

Townsend’s previous best result at a major tournament was when she reached the third round at the 2014 French Open at age 18. She next faces No. 15 seed Bianca Andreescu, who beat No. 19 Caroline Wozniacki, 6-4, 6-4.

“I’m here and I’m going to make it count,” Townsend said.

Andreescu missed most of the summer because of a shoulder injury but the Canadian returned to win the title in Toronto earlier this month. She hasn’t lost a singles match since March, though fell in the first round of women’s doubles on Friday to Townsend’s team.

“I kind of know what to expect. I know she loves coming to the net. She has incredible volleys,” Andreescu said. “I’ll for sure work on some passing shots tomorrow during my practice.”

Gauff, meanwhile, looked exactly like what she is: an immensely talented player who is still learning her way at tennis’ top level.

She pounded serves at up to 119 mph but also double-faulted seven times.

She overcame a slow start to get within 4-3 in the opening set but then dropped the last eight games.

“She told me I did amazing,” Gauff said during an unusual on-court interview for a match’s loser, something that was Osaka’s idea, knowing the way the packed house was supporting her opponent. “I’m going to learn from this whole match. She’s been so sweet to me.”

Osaka’s advantages in age – she’s 21 – and accomplishments – she is a two-time major champion, including at the Australian Open this January – played a role. So did her on-target power, which resulted in a 24-8 edge in winners.

“For me, this is the most focused I’ve been since Australia,” said Osaka, who’s had an up-and-down season since earning that trophy.

Addressing Gauff, she said: “I’m so sorry for playing you (with) this type of mentality.”

When it ended, after merely 65 minutes, Gauff began to bawl on the sideline. Osaka approached her and they spoke briefly. They’re both based in Florida now and have known each other for a few years. Their fathers are friends.

“I’ve watched her play for so long,” Osaka said. “I thought I had to get going right off the bat.”

American Kristie Ahn also added to her best performance in a Grand Slam by beating 2017 French Open champion Jelena Ostapenko, 6-3, 7-5. Ahn qualified for the U.S. Open in 2008 at 16 but then went to play collegiately at Stanford, helping the Cardinal win the 2013 national championship, and didn’t get back to another major until the 2018 Australian Open. She lost in qualifying at Flushing Meadows the last three years before earning a wild card this summer.

Rafael Nadal reached the fourth round in his 13th straight Grand Slam with a 6-3, 6-4, 6-2 victory over qualifier Hyeon Chung, a 2018 Australian Open semifinalist who has been slowed since by injuries. Nadal hadn’t played since Tuesday after receiving a walkover in his second-round match, but the three-time champion didn’t show any rust in a match he finished in just 1 hour, 59 minutes.

No. 6 Alexander Zverev and No. 28 Nick Kyrgios were also on the schedule, trying to reach the fourth round of the U.S. Open for the first time in what’s been an upset-filled men’s tournament. Zverev won in straight sets.

More than half of the 32 seeded men didn’t even make the third round, where a matchup Saturday between No. 14 John Isner and 22nd-seeded Marin Cilic, the 2014 U.S. Open champion, was the only match in the third round between two seeded players. Cilic won in four sets, 7-5, 3-6, 7-6 (6), 6-4.

The women’s field lost a top-10 seed when No. 7 Kiki Bertens was beaten 6-2, 6-3 by 26th seed Julia Goerges.