Rebecca Adlington has booked a place in the women's 800m freestyle final at London 2012.
The Beijing 2008 champion led her heat from the off, keeping her distance from closest competitor Lauren Boyle of New Zealand.
Adlington battled hard and looked impossible to catch, qualifying for the last eight with the fastest time of 8:21.78.
The final is expected to be a two-way battle between the world champion and Lotte Friis of Denmark, who recorded a landslide victory in her heat to clock up a time of 8:21.89.
Team GB's Ellie Faulkner struggled to keep up with the leading pack in her heat, and bowed out in seventh place.
The women's 800m freestyle final takes place at the Aquatics Centre tomorrow evening.
