Her comments after the race won Fu even more followers in China and around the world.
"At times, I felt like living was no better than death".
At age 15, she's earned global recognition after winning two medals at the 2011 World Junior Championships - a gold in the 100-meter backstroke and a bronze in the 200-meter freestyle.
And audiences enjoyed another showcase of Fu's animated reactions during her post-final interview, when she was completely oblivious to the fact that she had just won her first Olympic medal. Am I that fast?'
Fu won a bronze medal, finishing joint-third with Canadian Kylie Masse with a time of 58.76s, just 0.01s off of Kathleen Baker in silver.
At that point, the interviewer interrupted her.
And Fu Yuanhui has always celebrated in this way.
On China's Twitter-like Weibo, people have praised her for her genuine reaction and have also expressed gratitude at her efforts in representing China.
On Day 2, she got out of the pool after smashing a world record, walked up to a reporter for an interview.
The backstroker has become a social media hit in China for her amazed expressions - ranging from bewilderment to delight.
The 20-year-old simply couldn't believe that she had qualified for Sunday's 100m backstroke final, having finished third in a time of 58.95s.
Fu Yuanhui is proof you don't have to win a gold medal to have a golden personality.
"Well then I think that's not bad at all", said Yuanhui.
In a press conference after she was presented with her bronze medal, Fu said she was simply a "very happy person". Instead she is breaking the Chinese internet with her hilarious post-swim interviews.