Ellie Simmonds set a new Paralympic record to qualify for the final of the women's S6 400m freestyle final this morning.
The star of British Paralympic swimming clocked 5:24.64, with Natalie Jones also qualifying from the first heat.
Her main rival, American world record holder Victoria Arlen, won the second heat in 5:25.19 to set up an intriguing battle in tonight's final.
Simmonds was just outside Arlen's world record as she won her heat comfortably, ahead of Song Lingling in second and Jones in third.
The final is at 5.56pm in the Aquatics Centre tonight.