US sensation Simone Biles added the Olympic women's all-around to her team title for a second gymnastics gold title in Rio on Thursday. 

The 19-year-old was peerless as she crushed her rivals with a powerful display of acrobatics and tumbling in the Rio Olympic Arena.

She led a US 1-2 ahead of Aly Raisman with Russia's Aliya Mustafina taking her second straight Games all-around bronze.

It keeps three-time world all-around champion Biles' bid for a record five women's gymnastics golds on track with vault, beam and floor finals to come in Rio.

Biles finished 2.1 points ahead of Raisman, wrapping up the title with a dynamic floor routine which included her signature tumbling "Biles" move named after her.

The 1.45m (4ft 9ins) Texan, competing in her first Olympics, had already helped the US women to a second straight team gold. 

She launched her challenge by nailing a difficult Amanar vault scoring 15.866 despite a wobbly landing to lead Raisman by 0.233.

Mustafina pulled out 15.666 on uneven bars on which she is the reigning Olympic champion to lead at the half-way point by 0.034 as Biles hit 14.966 on her weakest apparatus.

Biles surged on front again with 15.433 on the beam as Mustafina dropped back after dropping back after errors.

The American led Mustafina by 1.533 going into the final floor rotation on which she is the reigning three-time world champion.

Raisman, the Olympic floor champion, pulled out a flawless floor routine to snatch silver which was only bettered by Biles.