“Any doubt is just a joke. Stress only makes us stronger,” Qin Haiyang – a part of China’s history-making men’s 4x100m medley quartet posted after their unprecedented victory over the US on Monday.

Qin’s seeming defiance came at the tail end of what has been a challenging time for China in the pool.

Some of the country’s top swimmers – including Qin and his relay teammate Sun Jiajun- have faced a slew of doping allegations, followed by contentious US claims that the World Anti-Doping Agency (Wada) was covering it up.

They were among 23 Chinese swimmers who returned positive doping tests ahead of the Tokyo Olympics.

And although Chinese swimmers have been drug-tested twice as much as some other nations this year before heading to Paris, their performance has been met with scepticism.

After the medley event on Monday, Team GB’s Adam Peaty opened fire on the Chinese team, saying “there’s no point winning if you’re not winning fair”.

Swim legend Michael Phelps, who has been vocal about doping issues, also doubled down: “If you test positive, you should never be allowed to come back and compete again, cut and dry. I believe one and done,” he told the Associated Press news agency.

To the Chinese swimming team and their millions of fans back home, however, the historic victory brought joy and vindication.

The hashtag “China wins gold medal at 4x100m medley relay” was viewed 760 million times on Weibo.

One comment racked up more than 8,000 likes on Weibo: “China’s gold medals are squeaky clean, we won it with our competence!”

“It’s been so hard for the Chinese swimming team,” read another top comment.

The immense pressure the team has been under was reflected in comments by China’s new breakout star Pan Zhanle, who swam the crucial anchor leg of the relay, and also won the men’s 100m freestyle final, setting a new world record.

After his win last week, Pan, who was not among those who tested positive for doping, told Chinese media that he felt that the whole team was “looked down on” by some foreign swimmers. He also said that Australia’s Kyle Chalmers had snubbed him when he tried to say hello – which Chalmers denied.

Pan’s record-breaking swim was questioned by former Australian Olympic swimmer Brett Hawke who posted on Instagram that it’s not “humanly possible to beat that field”.

It wasn’t the first comment of its kind. German athlete Angelina Köhler cast doubt on Zhang Yufei’s bronze win in the women’s 100m butterfly – she too was among the 23 who had tested positive in 2021.

Afte the swim, Köhler, who did not make the podium, reportedly told media that “stories like that always have a bad flavour”,

Zhang, who won a silver and five bronzes in Paris, was defiant.

“Why should Chinese swimmers be questioned when they swim fast? Why did no one dare to question USA’s Michael Phelps when he got eight gold medals?” she asked in a press conference.

The tension has spilled beyond the pool. China’s anti-doping agency (Chinada) released a statement on Tuesday, accusing its US counterpart Usada of displaying double standards.

The press release highlighted the case of US sprinter Erriyon Knighton, a world silver medallist who is competing in the men’s 200m sprint this week. He was not suspended after testing positive for the banned substance trenbolone earlier this year. Like in the case of the Chinese swimmers, the arbitrator had found the result was likely caused by contaminated meat.

Chinese fans, meanwhile, have been reacting furiously, to the accusaitons against the country’s swimmers.

Adam Peaty’s Instagram account was flooded with angry comments – even his girlfriend’s account was not spared.

“Curious why you’re only attacking China but none of the other countries that won ahead of you… pretty weird,” a top comment under Peaty’s most recent post reads.

Following a barrage of critcism from Chinese fans, Brett Hawke, the former Olympic swimmer who is now a coach, deleted the video he had posted about Pan. He also limited comments on his posts.

And a recent post about the men’s medley results says: “Chinese men are victorious!”