American gymnastics great Simone Biles remains on track for an unprecedented six gold medals at the Tokyo Olympics after beginning her campaign on Sunday, but she did not have it all her on way. Already regarded as one of the sport's all-time greats, Biles arrived in Tokyo targeting a record haul, including beating the mark of five gold medals at a single Olympics by a woman gymnast. Biles, 24, will have a packed program in Tokyo leading the US defence of their team title and her all-around crown while qualifying for the finals in the balance beam, asymmetric bars, vault and floor exercise. With no spectators allowed inside the Ariake Gymnastics Centre due to Covid-19 restrictions, it was very much a business-like effort by Biles and her teammates, although it was far from business as usual with a resurgent Russian team firing a warning shot. Russia, competing in Tokyo as representatives of the Russian Olympic Committee (ROC), have not won the women's team title since the 1992 Barcelona Olympics but lead with a mark of 171.629, more than a point clear of the US with 170.562. On the floor, Biles over-rotated after one series of mesmerising tumbles and went off the mat, drawing a gasp from at least one onlooker in the near-deserted Ariake Centre. She rolled her eyes after another unsteady landing over on the vault, and her performance director Tom Forster expressed disbelief after an untidy end to her beam routine. "Simone took three big steps on the beam dismount, I've never seen her do that before," he said. Biles qualified top in the all-around and vault, and was second on the floor, with the US occupying the same position behind the Russians for Tuesday's team final. But in the beam standings she paid for her flawed ending to lie sixth of the eight progressing. Biles also booked a place for the uneven bars final as the eighth qualifier. Biles later chose to focus on the USA's team title defence rather than any personal ambitions of adding to all the precious metal on her sideboard. "I feel we did a pretty good job," she said. "Obviously there are little things we need to work on, so we'll go back and practise and work on that, just so we can do our best performance at team finals, because that's what matters."