"You're kidding me?" state news agency Xinhua wrote (in a now-deleted post) on its official Twitter feed.
"The country which has never finished above China, is about to."
Olympic success is a point of pride for the Communist-run nation and athletes who perform well tend to be widely celebrated in the media.
The ruling Communist Party's official People's Daily was particularly upset with the performance of the Chinese gymnasts, who take home just two bronze medals.
"People cannot but ponder - what on earth is up with them?" it wrote.
As things stand, China could leave Rio with its lowest number of medals in 20 years.
But some commentators have started to refocus their support, choosing to just enjoy the events and praise the athletes for participating, rather than worry about medal tallies.
"The Chinese people have made progress, we don't need gold medals to boost our confidence and are no longer as harsh on our athletes," said one user on China's social network Weibo.
"What we chase now is the gold standard Fu Yuanhui reflects in her humour and innocence."
Fu Yuanhui is the bronze-medal swimmer who has entertained with her interviews, talking about topics including boys and her period.
After her team failed to get a medal in the women's 4x100m medley, a journalist asked her if she was OK.
Fu said: "I didn't swim well enough this time," and apologised to her team-mates.
"It's because my period came yesterday, so I felt particularly tired. But this isn't a reason, I still didn't swim well enough."
Ten million fans watched her talk live on a mobile app and she has been asked to appear on Chinese chat shows when she comes back from the Olympics.
Some of the sports where China tends to shine - badminton and diving for example - have seen them lose out to other nations.
The US tops the medals table, with 28 golds, while Team GB is second with 19 after 11 days of the competition.
China had a total of 51 medals by the close of play on Tuesday, one more than Great Britain.
But because it has fewer golds - 17 - it is ranked third on the leader board.
"Since China's gold opportunities are concentrated in the first half, it will be hard for China to win more than 25 golds at this year's Olympics, the lowest of the last five Olympics," the China News Service said on Sunday.
Since 2004, China has finished second on the medals table and when it hosted the Olympic Games in 2008 they won 51 gold, the highest they've ever claimed.
Going in to the competition, Chinese officials had warned of difficulties, blaming reasons including an unfamiliarity with South America and changes to the rules in some disciplines.
"After Beijing was selected as the host city in 2001, China started a long-term talent training plan for the Games," China's General Administrator of Sport Gao Zhidan told Xinhua in July.
"The plan continues but is not as vigorous as then. That will be another challenge."