PARIS — On Wednesday, she slept in the locker room through the torrential rain that initially delayed and ultimately canceled her quarterfinal and every other scheduled match at the French Open, then went shopping.

On Thursday, she returned to Roland Garros to contest the first match of her young career on the world’s most famous clay court, 15,000-seat Court Philippe Chatrier, against defending champion Simona Halep, no less.

None of these oddities and firsts rattled 17-year-old Amanda Anisimova, who needed just 68 minutes to topple Halep, 6-2, 6-4, and advance to the French Open’s semifinals as the last American standing.

The reason “I didn’t look nervous is because I wasn’t,” said Anisimova, who will face eighth-seed Ashleigh Barty of Australia on Friday for a place in the French Open final. “I was just super excited, and I was really happy with the opportunity. I felt really good today.”

Just two years removed from the junior circuit, the New Jersey-born Anisimova is one of a handful of steely-nerved, hard-hitting young female players to declare themselves credible contenders for major titles at this year’s French Open.

Like 20-year-old American Sofia Kenin, who ousted Serena Williams in the third round, Anisimova is of Russian descent and was coached since childhood by her Russian father. Konstantin Anisimov moved his family from Freehold, N.J., to South Florida when Amanda was 3, so she and her older tennis-playing sister, Maria Anisimova-Egee, could train more seriously.

Joining Anisimova in reaching the French Open’s final four is 19-year-old Marketa Vondrousova of the Czech Republic, who upset three seeded players on her march to her first semifinals of a major.

None of these young challengers — Anisimova, Vondrousova or Kenin — was seeded in the 128-player field. Yet all have displayed a tour veteran’s confidence, belief and sense of belonging in toppling favorites to post their best Grand Slam showings here at Roland Garros.

There was a sadly sparse crowd on hand to witness the biggest victory of Anisimova’s young career.

Wednesday’s rainout created a logjam of matches on Thursday, forcing officials to move up the start of women’s matches by two hours to ensure they could get the remaining men’s semifinals in, as well.

Halep and Anisimova, wearing identical Nike top and skirt, stepped onto Chatrier at noon, before many ticket-holders had come through the gates. With each knotting her long hair in a bun that sprouted atop a visor, only their five-inch difference in height made it easy to tell them apart from afar. Halep is 5-feet-6; Anisimova, 5-11.

Anisimova never gave the former world No. 1 an opening, pinning Halep behind the baseline by driving her groundstrokes deep on the red clay court.

The American teen played a steady, relatively consistent game, hitting 25 winners while committing 24 unforced errors, and broke Halep’s serve four times. Even when facing break point, Anisimova hit freely, with everything to gain and nothing of consequence to lose.

“I obviously respect every opponent I play; doesn’t matter what ranking they are,” Anisimova said, asked about the source of her courage and composure. “Yeah, I was going out there, and I'm playing Halep; she won last year. Obviously, I respect her a lot. But I know I'm capable of doing a lot. And I know I can play very well. I mean, I never doubt my abilities.”

The 27-year-old Halep, older by a decade, understood the dynamic and didn’t rule out the prospect of Anisimova becoming the first teenager to win the French Open women’s title since Monica Seles, who won her third in 1992, at 18.

“I think she has a big chance if she’s playing like today — without emotions and without thinking, like, about the result,” Halep said of Anisimova after the 68-minute rout. “She was pretty calm. She showed that she’s able to do good things and big things, so I think she has a chance.”

Meanwhile, on the slightly smaller Court Suzanne Lenglen, Barty was making quick work of American Madison Keys, dismissing the 14th seed in just 69 minutes, 6-3, 7-5.

“In a match like that, I have to be able to put some sort of pressure on her service games, and I felt like I wasn’t really doing that,” said Keys, a 2017 U.S. Open finalist, who was broken five times.

To catch up on the backlog of matches, French Open officials announced Thursday that they’ll hold both the men’s and women’s semifinals Friday.

Both women’s semifinals (Barty vs. Anisimova; and Britain’s Johanna Konta vs. Vondrousova) will start at 11 a.m. (5 a.m. Eastern time) and played be contemporaneously, on 10,068-seat Suzanne Lenglen and 5,000-seat Simonne-Mathieu, the second- and third-biggest venues on the grounds, rather than on Chatrier, as is customary.

The men’s semifinals — No. 2 seed Rafael Nadal vs. No. 3 Roger Federer, then No. 1 Novak Djokovic vs. No. 4 Dominic Thiem — will be played back-to-back, beginning at 12:50 p.m. (6:50 a.m. Eastern), on Chatrier.

Asked if she had any issues with the scheduling, Anisimova was initially puzzled upon learning that neither women’s semifinal would be played on Chatrier.

“Then where are they?” she asked, smiling.

Informed the women would be on Lenglen and Simonne-Mathieu, she seemed satisfied.

“It doesn’t really matter,” Anisimova said. “They're all beautiful courts. Whatever court they put me on to play in, I'm going to be happy.”

And what about the prospect of having to play three matches on consecutive days, without the customary days off in between? The 17-year-old embraced that, too.

“Actually, I’m really happy that I get to play tomorrow,” Anisimova said. “I don’t have to wait a whole day, because I get really eager to want to go on the court.”

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