BEIJING — After a week of turmoil rocking the Beijing Games, Kamila Valieva, Russia’s figure skating star, showed up at the Olympic rink on Thursday facing a single, heavy expectation: to win.

Gone was the 15-year-old clutching a pastel stuffed rabbit or giggling with her Russian teammates. In a mostly black costume with flame-red gloves that popped at the end of her long arms, she started off her performance to Ravel’s “Bolero” as if not a second of a doping dispute at the Games had fazed her, though she has been at the searing center of it.

The Russians came into the Games expected to sweep the medals in women’s singles and continue the country’s recent domination of the sport. Russians had won the past two Olympic gold medals in the women’s event, and Valieva’s job was to keep that streak going as the country’s top skater, already considered one of the best ever.

But after revelations that she had tested positive for a banned substance several weeks before the Games, reviving suspicions about a country already under punishment for doping violations, that task turned out to be just too much for her to handle.

Her Russian teammate Anna Shcherbakova, the reigning world champion, won the gold with a smooth and poignant performance, scoring 255.95 points. Her other teammate, Alexandra Trusova, won silver with 251.73 points. Kaori Sakamoto of Japan won the bronze with 233.13 points, saying she was both surprised and ecstatic about the medal.

Valieva, who was once considered invincible at these Games, finished off the podium, in fourth, with 224.09 points. She won the short program on Tuesday and had entered Thursday’s free skate in the lead; after a disastrous sequence of falls and stumbles, she wept as she left the ice.

A television feed showed her coach, Eteri Tutberidze, talking sternly to Valieva, wet with tears.

“Why did you let it go?” Tutberidze asked in Russian in a scene broadcast on live television. “Why did you stop fighting? Explain it to me, why? You let it go after that axel. Why?”

Valieva did not reply.

The turnabout erased any anticipated drama over a medal ceremony. Olympics officials had said that, with questions unresolved over Valieva’s drug test, they would not hand out medals in the event she won one, as they awaited a final determination in her case. The awarding of medals for the team event that Russia won last week, powered by Valieva’s remarkable performance, remains on hold as the Americans and the Japanese wait for silver and bronze.

After winning, Shcherbakova, 17, was in a light mood, expressing excitement about her own triumph.

“I was feeling a lot of pleasure because I happened to be in the right time and the right place and did the right things,” Shcherbakova said. But she quickly added, obliquely referring to Valieva’s situation, “On the other hand, I feel this emptiness inside.”

Trusova, also 17, was crushed after failing to win the gold. She had been sure that her icy, rocker’s performance to the “Cruella” soundtrack, in which she knocked out five quadruple jumps, landing three cleanly, was good enough to win.

After the results were in, cameras captured her weeping and screaming in anger, as she hesitated to return to the ice for a post-skate award ceremony. “I hate it!” she said. “I don’t want to do anything in figure skating ever in my life! Everyone has a gold medal, and I don’t!”

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Later, she told reporters, with her eyes rimmed with red from crying, “I am not happy with the result. There is no happiness.”

The Russians’ coach, Tutberidze, ended the day with another success for her program that is run out of a rink in Moscow. With Shcherbakova and Trusova finishing one-two, it is the second straight Olympics that Tutberidze’s skaters have won the gold and silver.

But here, Valieva was expected to be her star student, and it did start out that way.

In the team event, Valieva dazzled with her exquisite artistry and textbook jumps, including two quadruple jumps in the free skate, making her the first woman to land a quad at the Olympics.

But on Thursday, when Russia expected her to win convincingly, Valieva stumbled. Again and again and again. The crowd gasped in unison.

Although Valieva landed her first jump, a quad salchow, she fell on two other jumps, looking disoriented as she struggled to right herself. In a perplexing, uncharacteristic performance, she had errors on nearly every single jump, including her normally high-soaring quadruple jumps that she usually lands so softly there is barely a sound.

The audience felt so sorry for her that it started encouraging her with cheers. Her coaches, looking on from rinkside, did not join in. Tutberidze shook her head and, at one point, stared at the ceiling as her prodigy flailed on the ice.

After finishing their programs, Shcherbakova and Trusova both gave jubilant fist pumps. At the end of hers, Valieva punched the air in frustration. For what seemed like forever, she skated around the ice with a look of disbelief as if trying to figure out what had just taken place. Some fans began chanting, “Ka-mi-la!”

For the top three skaters, Valieva’s unexpected placement meant there would be a podium ceremony at the end of the night, with medals awarded in a separate ceremony Friday.

Shcherbakova, in her sparkly burgundy dress, posed for photos with the Russian Olympic Committee flag behind her. Valieva was nowhere to be found.

Valieva’s drug case continues.

She was found to have had the banned heart drug trimetazidine in her system several weeks before the Olympics. Later, according to documents from her hearing with arbitrators this week, it was found that Valieva had two other drugs in her system. Both of those are used by athletes to increase endurance but are not banned.

Valieva was cleared to compete in the women’s individual event just a day before it began with the short program on Tuesday.

According to an interview on Russia’s Channel One, the state-run TV station, she said she hadn’t slept at all on Sunday night after spending seven hours in a hearing with a panel of arbitrators considering her participation in these Games. In the end, the panel decided that barring her from competition would cause her “irreparable harm.”

“I’m happy but emotionally I’m tired, so this is tears of happiness, I think, mixed with a bit of sorrow,” she told Channel One. “But I’m surely happy to be at the Olympic Games and to try to represent our country, and I hope I will fully focus and demonstrate my results.”

This had been her goal since she was just a young girl growing up in Kazan, a city about 450 miles east of Moscow. And it was what she deemed possible even in those early years of skating when she rose quickly in the sport, pegged as a natural.

Years ago, a tiny Valieva dressed in a tiny white costume, straight out of “Swan Lake,” glided across the rink doing her tiny jumps and moving her body with a dancer’s soft arm positions and elastic legs. Even at that age, she moved so gracefully to the music that the notes seemed programmed into her DNA.

But on Thursday, she was a different Kamila Valieva, one whose name will forever be synonymous with one of the biggest doping controversies in Olympic history — the exact opposite of a little girl’s dream.

After learning that she had finished fourth, Valieva, clutching her worn stuffed rabbit, remained seated in the “kiss and cry” area, where skaters wait for their scores. And she sat and sat some more, frozen, as her coaches flanked her.

Eventually, she rose and disappeared behind a curtain and beneath the arena, with one coach — not Tutberidze — draping an arm over her shoulder. Some Russian fans applauded her as she left. With her head down, she walked past reporters waiting to talk to her.

Tutberidze’s other Olympians, like comets, have all faded away before a second Games, most gone after burning brightly, if fleetingly, in their success.

If history is a guide, other young skaters in the Russian sports machine are primed to take their place.

“Respected sports officials, you have destroyed the most talented figure skater in the world,” Andrei Zhurankov, a Russian commentator, said on television there. “You have destroyed the most bright figure skater in the world.”

Alan Blinder and Daniel Victor contributed reporting.