Simone Biles overcame kidney stone pain to help the USA women all-but guarantee a team final place at the Gymnastics World Championships in Doha.
The 10-time world champion gave a sparkling performance, scoring 60.965 over the four apparatus, less than 24 hours after having hospital treatment.
"It's been crazy. I got back from the emergency about 1am and they found I had a kidney stone," Biles told BBC Sport.
"But the pain is pretty OK right now."
She added: "I'm excited how today went and we'll keep good spirits for the team final and all-around."
The 21-year-old was making her return to international competition for the first time since she won four gold medals at the 2016 Rio Olympics, and also since she opened up about being sexually abused. .
"Before I walked out tonight I thought I can't believe it's Worlds already," Biles said.
"I feel like I wouldn't have even imagined a year ago starting to train, and coming back, so it's kind of crazy that I'm standing here."
Based on her showing in Doha, Biles also looks odds on to win a record fifth women's all-around title.
Of her four apparatus scores, her vault was the highest, with 15.966 for her first and 15.366 for her second - which was also a unique new skill performed for the first time in major competition.
Biles' floor routine was marginally lower at 15.333, while uneven bars (14.866) and beam (14.8) were also among the top scores so far in the competition.
"I never think about [records] until I see people mentioning them on social media," she said.
"I just try to focus on my routines and what I can do to benefit the team."
Her team have a comfortable lead in the qualification standings with further qualifying taking place on Sunday.