Kenya's Nicholas Bett has claimed gold in the men's 400m hurdles event at the World Athletics Championships in Beijing.
Bett ran a measured race to hold off his challengers in what was expected to be a tight final, finishing in a world-leading time this season of 47.79s.
Russia's Denis Kudryavtsev claimed a silver medal having qualified fastest at the Bird's Nest Stadium, while Jeffery Gibson of the Bahamas picked up bronze - both setting new national records.
USA's difficult day continued, however, as Michael Tinsley - a silver medallist in this event two years ago - blew a lead with an error-strewn final 200m.
The American hit a number of hurdles to eventually finish in last place, while compatriot Kerron Clement missed out on bronze by hundredths of a second.
