Biles nailed a spectacular Yurchenko double pike vault, sticking like glue on the landing.
It is a skill so difficult that no other woman attempts it in competition, and since Biles completed it at the World Championships it has been named for her as the Biles II.
"We would take this one in a heartbeat," Biles' coach Cecile Landi said. "Yeah, it was really good."
Landi said Biles was getting "more and more comfortable" with the skill, but Thursday's effort still stood out.
"She had one in the warmup gym that was also really good, but, no, I don't see it like that every day."
Biles is strongly tipped to add to her cache of four Olympic golds at the Paris Games after a tumultuous Tokyo campaign, when she withdrew from most of her events as she battled the dangerous and disorientating "twisties".
After a near two-year absence, Biles has quickly reestablished herself at the top of a sport she redefined with a unique combination of athleticism and artistry.
Meticulous attention to her mental health has the 27-year-old heading into her third Olympics on her own terms.
"Nobody's forcing me to do it," Biles said after earning her Paris berth. "I wake up every day and choose to grind in the gym and come out here and perform for myself -- just to remind myself that I can still do it."
She and her US teammates were all business as they got a feel for the competition arena, opening on balance beam, where Biles delivered some solid tumbling elements.
Moving on to floor exercise, Biles wowed with her triple-twist double flip but was a hair off in landing several of her impressive tumbling skills.
That took the Americans to the vault, where she offered a glimpse of just what everyone else in the field will be up against.
