Team GB's Stacey Tadd has crashed out of the women's 200m breaststroke at London 2012.
The 23-year-old got off to a strong start during her heat, but was unable to maintain the momentum, finishing 0.6s behind slowest qualifier Ganna Dzerkal of the Ukraine.
Pre-race favourite Rebecca Soni of the United States stormed through her heat to make the last 16 as the fastest qualifier on 2:21.40.
Her compatriot Micah Lawrence joins her in the semi-finals, where both face stiff competition from Denmark's Rikke Pedersen and Satomi Suzuki of Japan.
The women's 200m breaststroke semi-finals take place this evening at 8.27pm.
