In-form Puerto Rican 400m hurdler Javier Culson scored a psychological blow over British world champion Dai Greene at the London Diamond League meeting on Friday with an emphatic victory. Culson, unbeaten over the distance this season, romped home in 47.78secs at a rain-soaked Crystal Palace to equal the season\'s fastest time he had set in Paris last week as Olympic hopeful Greene trailed in second. The 27-year-old was always in control, flying out of the blocks to build an unassailable lead heading into the home straight and holding off a strong finish from Greene, who finished in 48.10sec. Two-time Olympic champion Angelo Taylor of the United States was third in 48.43. \"I would have loved to have won in front of my home crowd but my top-end speed needs to improve,\" said Greene. \"But I will continue working, I\'m running faster than last year. It should be a good Olympic final,\" he added. But it was a different story for British hopes in the women\'s 400m hurdles, with Perri Shakes-Drayton powering to victory over a strong field which included newly crowned European champion Irina Davydova. Shakes-Drayton, 23, obliterated her previous personal best of 54.18sec to come home in 53.77sec, equalling the second fastest time of the year set by Davydova, who was second in 54.63sec. Kaliese Spencer of Jamaica was third while compatriot Melaine Walker, the reigning Olympic champion, was a distant fourth.