How Simone Biles overcame childhood hunger and sexual abuse to become world's greatest gymnast
Olympic champion Simone Biles has pulled out of the gymnastics team finals due to a "medical issue".
A statement from USA Gymnastics said: "Simone Biles has withdrawn from the team final competition due to a medical issue. She will be assessed daily to determine medical clearance for future competitions."
The record-breaking American athlete had a rocky start in the final, where the US is looking to secure a third straight Olympic title.
The 24-year-old bailed on her planned Amanar vault, opting for an easier one in mid-air, and then struggled with the landing.
The rare misstep allowed the gymnasts from Russia to open up a one-point lead after the first rotation.
Biles huddled with a trainer after landing her vault.
She then exited the competition floor with the team doctor before returning several minutes later with her right leg wrapped.
She took off her hand grips, and hugged teammates Grace McCallum, Sunisa Lee and Jordan Chiles before putting on a jacket and sweatpants.
Vault has long been a strong suit for the US and Biles is the defending Olympic and world champion in the event.
It raises questions about whether she participate with the Women's All Around final on Thursday.
Biles had opened up about the pressure she feels this Olympic Games following a less than perfect performance on Sunday.
The team representing the Russian Olympic Committee (ROC) came first in qualifying, becoming the first in 11 years to beat the US in any portion of a major international competition.
In a post on Instagram Biles said she had "the weight of the world on her shoulders".
"It wasn't an easy day or my best but I got through it," she wrote from Japan on Monday morning.
"I truly do feel like I have the weight of the world on my shoulders at times.
"I know I brush it off and make it seem like pressure doesn't affect me but damn sometimes it's hard hahaha! The Olympics is no joke! BUT I'm happy my family was able to be with me virtually they mean the world to me!"
Biles was tipped for another five gold medals in Tokyo to add to the four golds and one bronze she won in Rio in 2016.
She has 19 world championship gold medals.
The US has won every team gold in every Olympics since 2011. But the athletes representing the Russian Olympic Committee were leading in the team final with one rotation left to go.
There was also a huge upset in the tennis, with Japan's Naomi Osaka - also one of the stars of the Games - beaten by Marketa Vondrousova of the Czech Republic 6-1, 6-4 in the third round.
Osaka, who lit the Olympic cauldron in Friday's opening ceremony, had won her opening two matches in straight sets.