The time was three seconds faster than her result at the world championships and broke the Asian and national record of 2:07.57 set by Ye Shiwen at the London Olympics in 2012 — before Yu was even born.

"I didn't see my time clearly," she admitted. "Suddenly I heard that the Asian record had been broken, and I was wondering who broke it. I didn't expect it to be me!" Yu called the moment "unbelievable", adding: "I had only one feeling — I wanted to cry!"

Her surprises did not end there. In the 200m butterfly, she surged ahead of Zhang Yufei, one of China's most accomplished swimmers. Before the race, Zhang had gently patted Yu on the shoulder.

Zhang later explained that she wanted Yu's path to be smooth, but also hoped she would encounter moments that would help her grow. A completely smooth journey, Zhang said, is not always ideal for an athlete — but she also didn't want Yu to lose confidence because of any setbacks.

Yu continued her momentum by helping the Hebei team win gold in the women's 4X200m freestyle relay. Her split time of 1:57.98 was the fastest she had ever swum.

Looking back on her overall performance at the National Games, she gave herself a score of 90. "I'm generally satisfied," she said. "I did my best in the races, but there are still areas I can improve, especially my breaststroke technique. I will keep working hard and try to do even better next time."

After the swimming program ended, Ye approached her with a smile. "When I broke the world record in the 400m individual medley, I was also wondering who it was that had broken it," Ye told her. "Your feeling today was just like mine."

Ye said she was sincerely happy to see her own record fall.

"Records are meant to be broken," she said. "Congratulations to Yu for beginning her own era. I'm very happy to see such a strong new generation in Chinese swimming, and I look forward to seeing her continue to perform miracles for China on the international stage."

Yu's journey in the water began with something much simpler than medals or records — a summer filled with play. When she was six, her father used to take her to a water park, where she discovered an instinctive joy in the water.

While other children hesitated or clung to floats, Yu seemed to merge with the element, floating effortlessly and paddling forward with a natural rhythm. Her instinctive "water sense" caught the eye of Li Chao, a coach with the Baoding swimming team, who happened to see her at the pool.

"She wasn't the kind of child who was especially outgoing," Li recalled. "But once she got into the water, she was completely different.