But nothing was more remarkable than that her split time for the final 50m of the freestyle leg was quicker than that of Ryan Lochte in the men’s race earlier that same evening. It was the first time that had happened in Olympic history.

When Lochte swam to gold, leaving Michael Phelps far in his wake in fourth, he clocked a final 50m freestyle time of 29.10sec.

In her race, Ye went surging through the water, past world champion Elizabeth Beisel, and recorded a final 50m time of 28.93. “Yeah, we were talking about that at dinner,” Lochte said. “It is pretty impressive. She’s fast. If she was there with me, she might have beat me.”

The scary thing, or at least one of the scary things, for Hannah Miley and the rest of the world’s women medley swimmers, is that the 400m medley is not even Ye’s strongest event.

She swims in the heats of the 200m medley on Monday morning, an event in which she is the world champion, having won the title in Shanghai last summer as a 15-year-old.

She thinks she can get better, too. “There’s much room for improvement,” Ye said. “It’s true for breaststroke I am lagging behind but I think my freestyle result is also not that good.

“Usually I’m very bad at turning. This is one of my worst basic skills, but turning is a very important skill, therefore I was practising my turns before the competition.”

Another scary thing is that her time of 4min 28.43sec not just broke the world record, but did so by more than a second.

The previous best of 4-29.45 had been recorded by Stephanie Rice in the Olympic final four years ago, and that done with the aid of a polyurethane suit, which has since been banned. It was an incredible performance and one, therefore, that drew attention to its own credibility.

Chinese swimming has such a shameful history of doping that any remarkable achievement by one of its athletes is inevitably met with cynicism. In the 1990s more than 40 swimmers tested positive for doping.

In the 1994 world swimming championships, China won an improbable 12 gold medals and later that year seven swimmers tested positive for steroids at the Asian Games. At the following Olympics in Atlanta in 1996, they won just one gold.

Just this weekend, Chen Zhanghao, the doctor with the Chinese Olympic team at the Los Angeles, Seoul and Barcelona Games, told Australia’s Sydney Morning Herald newspaper he had tested hormones, blood doping and steroids on about 50 elite athletes.

While the Chinese swimming authorities insist that their sports has cleaned itself up, five swimmers were banned for failing a test in 2009 and, even more worryingly, 16-year-old Li Zhesi tested positive for EPO in an out-of-competition test on March 31 of this year.

Li had won gold as part of the 4x100m freestyle team in 2009 and might have been in London had she not failed the drugs test.

Patrick Miley, Hannah’s father and coach, said he had been surprised by Ye’s time. “It was a remarkable performance,” he said. Was it credible, though, beating Lochte in that final split? “She is an excellent freestyle swimmer,” was all Miley said in answer.

“The Chinese got it right this time,” he said. “I cannot control what other people do. The sport is really exciting and amazing things do happen.

“This swimmer has progressed the event. I had a conversation with the sporting director of Scottish swimming four or five years ago in which I said I thought 4.25 was something that would be there in the not too distant future, that it would happen in my lifetime. Everything progresses.”

Even with her Chinese rival swimming quicker than Lochte, Miley could have made the podium if she had hit the personal best she was seeking.

“Hannah’s only disappointment will be that she wanted to swim a time that was the best she had ever swum. And it wasn’t,” Patrick said.

“The irony is that that time would have put her on the podium. That is why she is hard on herself. I mean she came here in the trials and did a time that would have won her the bronze medal.”

The 400m is Miley’s stronger distance and things are not going to get easier racing against Ye in the 200m. Her father, though, believes that with the pressure off, Miley is still capable of competing with the best.

“She has the 200m medley to come and she will enjoy it,” he said. “It is from a different perspective which might just allow her to do something very special.”

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