RIO DE JANERIO (AFP) - Simone Biles produced a powerful display of acrobatics to power a dominant United States top of women's gymnastics qualifying at the Rio Olympics as Gabby Douglas's all-around title bid ended on Sunday.
The 19-year-old Biles lead a US 1-2-3 in the all-around ahead of team-mates Aly Raisman, 22, and Douglas, 20, but the two per country rule means that the latter will not be able to defend her title on Thursday.
Olympic rookie Biles scored 62.366 points after the four rotations with Raisman, who finished fourth in London 2012, on 60.607, and Douglas just behind on 60.131.
The five-woman US team, winners in 2012, lead 2008 Olympic champions China by over ten points with Russia third after four of five subdivisions with Japan, Canada and France competing later Sunday.
Biles, the reigning three-time all-around world champion, herself remains on track for five gold as she scored highest on vault (16.050), beam (15.633) and floor (15.733).
American Madison Kocian led the way on uneven bars on which she shared gold at last year's worlds. The tiny Texan started on floor with a routine of mesmerising high-speed acrobatics and tumbling topped by her signature move - the Biles - a tumbling double half layout, complete with full twist.
She followed on the vault with her first effort a soaring Amanar - a back handspring with a layout with two-and-half twists. The record ten-time world champion's third rotation - uneven bars - was solid and she finished off in style on the beam.
Douglas, the first African-American to win all-around gold and then help the United States to the women's team title in 2012, had been bidding to become the first woman since 1968 to win back-to-back all-around gold.
She took time off after her London success with Biles dominating women's gymnastics in her absence. Douglas is also sure to compete in the uneven bars final.
The top 24 gymnasts advance to the all-around final with eight nations qualify for Tuesday's team final.