As she had insisted in a tweet on Friday, the kidney stone problem, which kept her in the emergency room for several hours less than 24 hours before she competed, was no showstopper.
The American was not only first in the all-around but also vault, beam and floor qualifying and second in uneven bars through five of the qualifying groups.
That she went ahead with the competition was not surprising, said U.S. team high performance director Tom Forster.
"She's Simone, you would expect the same out of a Michael Jordan or a Tiger Woods and that's who she is in our sport," Forster said.
Despite the pain, Biles had a sense of humour about the episode.
"I heard roller-coasters may help kidney stones and I am basically my own little roller-coaster out there," she said after competing on Saturday.
"It has been a rough 24 hours but I am definitely better than yesterday. Yesterday I was kind of crawling on the floor. Today I can stand, so it's better.
"Without my team mates I don't think I would have the confidence to go out there and do the routines I did. I am here for the team."
Because the competition is important to her, Biles said she planned to wait until after the championships to deal with the kidney stone, which means she will likely be in pain throughout the next seven days.
Winner of four gold medals and a bronze at the 2016 Rio Olympics, the 10-times world champion had taken 2017 off before successfully returning to competition earlier this year.
Her performance and that of team mate Morgan Hurd put the United States in first place in qualifying, well ahead of Japan.
(Reporting by Gene Cherry in Wilson, North Carolina; editing by Ken Ferris/Greg Stutchbury)
