Peng could be seen in the stands wearing a black knit hat with the Olympic rings on them and a black coat with the Chinese flag.
Peng's presence during the Games had been a matter of speculation since the IOC said it planned to meet with her in Beijing.
Serena Williams voiced concern for fellow tennis player Peng Shuai, who has not been seen publicly since she accused a former vice-premier of China, Zhang Gaoli, of sexual assault.
Chinese tennis star Peng Shuai, whose whereabouts have been a matter of international concern for weeks, attended a tennis tournament in Beijing on Sunday.
Sania Mirza reached her first Grand Slam semi-final of the year with China's Shuai Peng after outclassing Timea Babos and Andrea Hlavackova in the women's doubles, at the US Open, in New York.
Second seed Venus Williams avoided a second defeat within 24 hours at the hands of Shuai Peng as she scraped past the Chinese in the second round of the WTA Bangalore Open on Thursday evening.
Chinese veteran Peng Shuai beat American Alison Riske 7-6(3), 6-2 in the final of the Tianjin Open to capture her first Tour title on Sunday.
The Indian ace, who made it to the main draw of the Family Circle Cup through the qualifying rounds, won the first set 6-2, but failed to sustain the pace in the next two sets, which she lost 2-6, 2-6.
Tennis great and founder of the WTA Billie Jean King was among those who applauded the announcement.
Yao said he and Peng had known each other for nearly 20 years. However, he did not comment directly on the controversy that flared up last year after Peng, a former world No. 1 doubles player, appeared to allege that a former vice premier, Zhang Gaoli, had sexually assaulted her in the past.
In her now-deleted post on China's Twitter-like Weibo, Peng had written "why did you take me to your house and force me into having relations with you?", though she also described the relationship with Zhang as an on-off one that was also consensual.
A long measure of Grand Slam patience paid off for Peng Shuai of China, who reached the semi-finals of the US Open on Tuesday by routing Swiss teenager Belinda Bencic 6-2, 6-1 in the Flushing Meadows heat.
World No 1 doubles player Sania Mirza's campaign in the women's tennis event came to an end as she and her partner Prarthana Thombare lost their first round match to the Chinese pair of Shuai Zhang and Shuai Peng. Zhang and Peng won a closely contested match 7-6(8-6), 5-7, 7-5 that lasted two hours and 44 minutes.
Peng Shuai of China upset fourth-seeded Agnieszka Radwanska of Poland 6-3, 6-4 in a shocking start to the women's second round of the U.S. Open on Wednesday.
An outcry over the whereabouts of Chinese tennis star Peng Shuai escalated on Friday as the Women's Tennis Association (WTA) said it was prepared to pull its tournaments out of China if they were not satisfied with the response to her sexual assault allegation.
Djokovic says Peng situation horrifying, says tennis must unite.
Indo-Chinese pair were beaten 6-4, 6-4 by second seeds Martina Hingis and Yung-Jan Chan on Friday.
Chinese tennis star Peng Shuai said on Sunday that she had never accused anyone of sexually assaulting her, and that a social media post she had made early last month had been misunderstood.
Sania Mirza and Rohan Bopanna have reached the quarter-finals of their respective events at the US Open but the fledgling partnership of Leander Paes and Purav Raja has fallen flat yet again.
Hsieh Su-wei became the first Taiwanese player to win a grand slam title when she and Peng Shuai beat Ashleigh Barty and Casey Dellacqua 7-6(1), 6-1 in the Wimbledon women's doubles final on Saturday.
Rohan Bopanna's campaign at the last Grand Slam of the season ended with defeat in the mixed doubles along with Canadian partner Gabriela Dabrwoski while India's juniors also fizzled out in the singles in the US Open in New York.
Former French Open champion Michael Chang is no longer coaching China's Peng Shuai but still believes he could help Chinese chances of winning medals at next year's Beijing Olympics
Maria Sharapova set up an enticing quarter-final showdown with Eugenie Bouchard at the Australian Open following a comfortable 6-3, 6-0 fourth round victory over China's Peng Shuai on Sunday.
India's leading doubles players Rohan Bopanna and Sania Mirza began their US Open campaigns with victories in their respective events.
They beat wild cards Svetlana Kuznetsova and Amelie Mauresmo 6-4, 6-4 in the first round at the Dubai Open.
The United States and Britain had also called for China to provide proof of Peng's whereabouts.
Rohan Bopanna and Sania Mirza bowed out of the Cincinnati Masters after losing their quarter-final and semi-final matches with their respective partners in the men's and women's doubles.
President Pranab Mukherjee on Tuesday congratulated tennis ace Sania Mirza for winning the season-ending WTA Finals women's doubles title.
Sania Mirza and Jie Zheng moved into the semi-finals of the women's doubles with a straight sets win over Su-Wei Hsieh and Shuai Peng.
India's tennis ace Sania Mirza and Cara Black showed nerves of steel as they saved three match points in the Super Tie Break against Kveta Peschke and Katarina Srebotnik to cruise into the summit clash of the WTA year-end finals, in Singapore on Saturday.
Indian ace Sania Mirza and her Zimbabwean partner Cara Black ended the season and their partnership on a remarkable high by clinching the WTA finals women's doubles title with a comprehensive triumph in the summit clash in Singapore.
Milestones in the progress of Chinese women's tennis after Li Na, the first Asian to win Grand Slam singles titles, announced her retirement from the sport on Friday.
Prime Minister Narendra Modi congratulated Indian tennis ace Sania Mirza on winning the season-ending WTA Finals women's doubles title, calling it a 'proud accomplishment'.
Women's No 1 Serena Williams remained on track for her 60th career title as she powered past Peng Shuai 6-2, 6-3 while Rafael Nadal launched the defence of his Madrid Open title.
Sania Mirza lifted with partner Nadiia Kichenok pipped the second seed Chinese team 6-4, 6-4 in one hour 21 minutes.
Winter Olympics will be staged by a country that has grown far wealthier, more powerful
Sania Mirza played without pressure, and insisted there was no secret to the swift success on comeback.
World number two Dinara Safina battled into the fourth round of the WTA event in Indian Wells on Sunday, beating Peng Shuai of China 7-5, 6-4. Fourth seed Vera Zvonareva of Russia booked her place in the last 16 with a routine 6-3, 6-1 win over Czech Petra Kvitova.
Zhang Shuai was aware of the risks involved when she opted to "Fly Alone" two months ago but the 24-year-old Chinese now stands vindicated after winning her maiden WTA Tour title on Saturday.
