World Athletics 2013: Dai Greene into 400m hurdles semis
Defending champion Dai Greene reached the semi-finals of the 400m hurdles despite struggling in his heat.
The 27-year-old, who has suffered from injury and illness this year, was fifth in 49.79 seconds.
That would have left him relying on a fastest-loser place, but he was moved up to fourth after Puerto Rico's Eric Alejandro was disqualified.
In the women's event, British champion Perri Shakes-Drayton set the fastest qualifying time with 54.42.
Compatriot Eilidh Child is fourth fastest going into the semi-finals after finishing second in her heat in 55.17, while Meghan Beesley, 23, made it a hat-trick of British qualifiers after also finishing second in her opening race.
Two leading contenders for a medal failed to make the next round. American Georganne Moline bowed out after falling and finishing last, while Kaliese Spencer of Jamaica was disqualified for a lead-leg infringement.
In the men's event, two other Britons joined Greene in the semi-finals. Fellow Welshman Rhys Williams finished fourth in his heat in 49.85 and Seb Rodgers, who won gold in the Under-23 European Championships in Finland last month, qualified after finishing fifth in his heat in 49.66, the same time as the fourth-placed athlete.