China’s most decorated swimmer has made a winning return to the pool after serving a controversial four-year drugs ban.

Sun Yang won gold in the men’s 400m freestyle at China’s National Summer Swimming Championships in Hefei on Sunday – and then broke down while speaking to reporters.

He had been previously vilified by many in China as a drugs cheat, but his return was praised across state media.

His win on Sunday comes shortly after a highly publicised anti-doping row at the Paris Olympics this summer, in which China said its athletes were being unfairly targeted.

In a tearful poolside interview with reporters, the 32-year-old thanked those close to him for helping him get back to competing.

“This is really because of the reliance and support from my family — that’s what’s kept me going until today,” he told the South China Morning Post.

Sun was suspended by the Court of Arbitration for Sport (Cas) in 2020 for refusing to provide samples for testers who had visited his home.

In 2012, Sun became China’s first male swimmer to win an Olympic gold when he came first in the 400m and 1,500m freestyle races in London. Four years, he followed this up with another gold in the 200m freestyle at the Rio Olympics.

But his career came crashing down when anti-doping officials visited his home in 2018 for an out-of-competition test.

Sun and his team said the testers lacked the proper accreditation and refused to co-operate with them.

According to the testing team, a member of Sun’s entourage smashed a vial of his blood with a hammer to prevent them from departing with the sample.

Sun – who had already been suspended for three months in 2014 for using the banned substance Trimetazidine (TMZ) – denied any wrongdoing and he was initially cleared by swimming’s governing body Fina.

Two years later, however, CAS overturned the decision and ruled that Sun had refused to cooperate with the sample testers. He was given an eight-year ban, which was later reduced to four years and three months on appeal.

As he had never technically tested positive for any banned substances, Sun was allowed to keep all of his medals.

His victory on Sunday was widely hailed in Chinese state media outlets, whose posts on social channels were flooded with positive comments.

“Brother Sun, don’t cry. The past four years haven’t been easy. You’re amazing,” said one user on Weibo.

Another said: “Congratulations to Sun Yang. Four years and three months of determination and perseverance have all been worth it and have led to this moment. Looking forward to Los Angeles.”

Chinese swimmers have been in the spotlight since the Paris Olympics after a slew of doping allegations, followed by contentious US claims that the World Anti-Doping Agency (Wada) was covering it up.

Those who headed to Paris were drug-tested twice as much as some other nations, which, in turn, has fuelled accusations of a conspiracy to disrupt their performance.

At the time, the state-run Global Times blamed Western powers for “abusing doping tests to disrupt [the] Chinese swimming team”, while breaststroke champion Qin Haiyang accused opposing teams of using underhand “tricks” to disrupt Chinese competitors.

In his long-awaited return, Sun represented his home province of Zhejiang – but it is unclear whether he will be allowed to represent China on the international stage.

According to the country’s anti-doping regulations, athletes who have been banned for more than one year are not eligible to be selected for the national team.

Sun insists he will “go all out” to compete for a spot in the 2028 Olympics in Los Angeles – although his performance will need to drastically improve.

His race on Sunday featured no competitors who swam in the Paris Olympics and his time was nearly nine seconds slower than his previous best, which he clocked in London in 2012.

“I could have done better. Four years away from competition and without intensive training, I do feel rusty in controlling the tempo, and I need more competitions,” he told state-run outlet China Daily.

“But it’s a good start for my comeback, and I’m happy with this result,” he added.