Moscow - The United States hopes of a medals clean sweep in the 110 metres hurdles remained intact as all four of their hurdlers qualified for the final later on Monday at the World Athletics Championships.
Defending champion Jason Richardson timed 13.34 seconds to win a high class first semi-final in Moscow which involved all three Olympic medalists.
Richardson, 27 and who took silver at the Olympics, led from the off and had plenty to spare as he crossed the line ahead of Frenchman Thomas Martinot-Lagarde while Olympic champion Aries Merritt was third.
Jamaica's Olympic bronze medalist Hansle Parchment looked set to qualify but hit the penultimate hurdle and, off balance, failed to clear the final one, falling to the track in despair.
Barbados's 2009 world champion Ryan Brathwaite also failed to make the final as he finished last in the same semi-final.
Richardson's and Merritt's two team-mates David Oliver, the fastest man in the world this season, and Ryan Wilson had no problems qualifying automatically from the second semi-final.
The duo were content to ease up and allow Russian high hurdler Sergey Shubenkov to have his moment of glory in front of his home crowd and win the race in 13.17sec.