Peng Shuai, the Chinese tennis star whose account of sexual coercion by a former Communist Party leader ignited weeks of tensions and galvanized calls for boycotts of the Winter Olympics in Beijing, has reversed her assertion that she had been sexually assaulted by the official.

Ms. Peng made the comments in an interview that was published on Sunday by a Singaporean newspaper. But the retraction appeared unlikely to extinguish concerns about her well-being and suspicions that she had been the target of well-honed pressure techniques and a propaganda campaign by Chinese officials.

The controversy erupted last month when Ms. Peng wrote in a post on Weibo, a Chinese social media platform, that she had maintained a yearslong, on-and-off relationship with the retired Chinese vice premier Zhang Gaoli, now 75. She said that in an encounter with him about three years ago, she had “never consented” and that she was “crying all the time.”

She then abruptly dropped from public view, and global concern for her whereabouts grew. In a written statement later, she appeared to seek to pull back the accusation, and the Women’s Tennis Association and other professional players rallied to her side, saying they believed that her statement had been written under official duress.

The tennis association suspended playing matches in China while seeking to establish independent contact with Ms. Peng. Last week, the leaders of the United States Olympic and Paralympic Committee criticized China’s handling of Ms. Peng’s case.

In the interview with Lianhe Zaobao, a Chinese-language Singaporean newspaper, Ms. Peng, 35, said, “First, I want to stress a very important point — I never said or wrote that anyone sexually assaulted me.”

“There may have been misunderstandings by everyone,” she said of her initial post on Weibo.

Ms. Peng also denied that she had been under house arrest or that she had been forced to make any statements against her will.

“Why would someone keep watch over me?” she said. “I’ve been very free all along.”

Her denial drew skepticism from human rights advocates, who have said that Chinese officials appear to have corralled her into rehearsed video appearances.

Kenneth Roth, the executive director of Human Rights Watch, said on Twitter that Ms. Peng’s latest statement was “only deepening concerns about the pressure to which the Chinese government is subjecting her.”

Last month, video clips of her at a Beijing restaurant were posted on the Twitter account of the chief editor of The Global Times, an influential newspaper run by the Communist Party. The editor described them as showing Ms. Peng having dinner with her coach and friends. She also appeared in live video calls with the president of the International Olympic Committee and other officials with the organization.

The Chinese authorities are likely to seize on Ms. Peng’s latest statement, recorded on video, to push back against calls for a full investigation of her claims and to oppose the tennis association’s suspension of matches in China.

The minutes-long interview with Ms. Peng, which took place at a skiing competition in Shanghai, left many key questions unasked and unanswered.

She was not asked directly about her relationship with Mr. Zhang, who was a member of the Politburo Standing Committee, the Communist Party’s highest body. Nor was she asked how her understanding of sexual assault squared with her earlier description of what had happened with Mr. Zhang.

Ms. Peng has been one of China’s highest-ranked tennis players, reaching No. 1 in doubles in 2014 and as high as 14th as a singles player. Her Weibo account in early November of her relationship with Mr. Zhang lasted for all of 20 minutes before Chinese censors erased it. But the news quickly spread online.

Since then, the Women’s Tennis Association and other organizations have pressed the Chinese authorities to ensure Ms. Peng’s safety and to give her a chance to recount freely what had happened with Mr. Zhang.

The interview published on Sunday came after the international arm of China’s state broadcaster, China Global Television Network, publicized an English-language email in Ms. Peng’s name in November. In it, she denies the sexual assault accusations and asks to be left alone.

But Steve Simon, chief executive of the Women’s Tennis Association, and many rights activists have raised doubts about its authenticity.

In the latest interview, Ms. Peng appeared to try to address those doubts. She said she had written a Chinese statement along those same lines “entirely of my own free will,” and then someone had helped her translate it into English.