Team GB's Fran Halsall has clinched a place in the women's 50m freestyle semi-finals at London 2012.
The 22-year-old flew through her heat in 24.61s to hit the side ahead of world champion Britta Steffen of Germany.
Halsall makes the last 16 as the third-fastest qualifier, behind 100m gold medallist Ranomi Kromowidjojo of the Netherlands and her compatriot Marleen Veldhuis.
Great Britain's Amy Smith faces a swim-off after finishing in joint-16th place overall with Kara Lynn Joyce of the United States, and Sarah Blake Bateman of Iceland.
The women's 50m freestyle semi-finals take place at the Aquatics Centre this evening.