The seven-times gold medallist was widely expected to win another one but came second and fifth in Monday’s events.
Simone Biles has suffered double disappointment at the Paris Olympics after missing out on gold in both the balance beam and floor exercise events.
The US gymnastics sensation took a silver medal in Monday afternoon’s floor exercise after a routine that included a couple of costly steps out of bounds, failing to repeat her gold in Rio de Janeiro eight years ago.
Brazil’s Rebeca Andrade captured gold, becoming the first gymnast to beat Biles in a floor final in a major international competition.
Andrade scored 14.166, narrowly ahead of Biles at 14.133 while Jordan Chiles earned the bronze.
A defiant Biles said: “I can’t be more proud of how I’ve done. I’m 27 years old walking away from this games with four medals to add to my collection. Not mad about it.
“I’ve accomplished way [more than I thought I would]. A couple of years ago, I didn’t think I’d be back here.”
The seven-time Olympic champion had already won golds in the team all-around, individual all-round, and vault events, in the French capital.
Biles’ Olympic medals total of seven golds, two silvers and two bronzes puts her joint second in the all-time female gymnastics list with Czechoslovakia’s Vera Caslavska.
She was widely expected to secure her fourth – and possibly fifth – gold in her last events of these games on day 10.
But she had already proved she is only mortal after all when she fell off the beam midway through her women’s balance beam final routine, an event won by Italian Alice D’Amato.
There was a loud “ohhh” from the thousands of fans – including NFL great Tom Brady – inside a packed Bercy Arena as she lost her balance and had to hop off the apparatus and onto the mat.
Biles recovered to finish her performance and received a score of 13.100, tying her with US teammate Sunisa Lee for fourth, but slipped one place further down by the end of the final.
As she waited for her score, Biles rolled her eyes in seeming annoyance knowing she was not going to finish on the podium.
Her total was well below D’Amato’s winning score of 14.366, with China’s Zhou Yaqin taking silver and another Italian, Manila Esposito, coming third.