They don't compete over that distance at the Olympics, so Fu's aim in Rio was to improve on the eighth-placed finish in the 100m backstroke she recorded in London 2012.
That looked unlikely after the heats, as Fu qualified ninth fastest for the semi-finals. But she dropped more than a second off her heat time in the semis to finish third and qualify for the final.
Interviewed poolside by a Chinese broadcaster, Fu was blown away when the reporter informed her she'd actually broken the 59 second barrier. "58.95?! I thought I did 59 seconds! Wow! Am I so fast? I am very pleased!" she said.
Reporter: "Did you somehow reserve your energy?"
Fu: "No no, not at all ... I've been utilising prehistoric powers. This is my best score ever!"
According to shanghaiist.com, Fu's reaction became the most popular topic on Chinese microblogging service Weibo and inspired imitations among China's 1.3 billion population, including one from well-known Chinese actor Jia Nailiang. Fu's personal following on Weibo quickly climbed towards two million.
"She is my goddess," one Chinese follower wrote. "Everyone will love her after seeing the interview."
But she wasn't finished there. The following night Fu lined up alongside Australian duo Emily Seebohm and Madison Wilson in the final.
Swimming in lane three, Fu went quicker again to touch the wall in a dead heat for third behind Hungarian winner Katinka Hosszu and American's Kathleen Baker.
But as she trudged over to the same broadcaster for another interview, Rio's new sweetheart believed Canada's Kylie Masse had beaten her home.
She appeared to fight back tears as she spoke with resignation about her Olympic experience, but attempted to look on the bright side saying, "even though I didn't win a medal ...".
"But you got a medal, you are third," the reporter interjected.
Fu: "Huh? What?! Third?"
Reporter: "You didn't know? You came in third!"
Fu: "I did not know (looks around with puzzled look). Well (smiling), then I think that's not bad at all!"
That's right Fu, not bad at all.
