Kerron Clement of the United States dipped on the line to win the men’s Olympic 400 metres hurdles yesterday after one of his leading rivals, Puerto Rico’s Javier Culson, was disqualified for a false start.

The long-striding Clement led down the home straight and was still clear as he entered the closing metres. But he had to lean into the tape to deny Kenya’s Boniface Tumuti, charging up fast two lanes to his right.

“I fought the last 100 metres because I knew the guys would be coming. The last few metres I just dug down deeper,” Clement said after clocking 47.73 seconds to win by 0.05 of a second.

Culson, 32, bronze medallist in London in 2012, blew his chance by jumping the gun, and briefly sat sobbing by the side of the track before trudging away.

“When he false-started I just said to myself: ‘Refocus’,” Clement told reporters.

“The adrenaline rush just zapped him out.. I tried not to let it affect me and just focus on the 10 hurdles in my lane again.”

Tumuti said he had “lost the gold dream” with a miscalculation on the approach to the seventh hurdle.

Turkey’s Yasmani Copello won the bronze and told reporters: “I think my mother is crying. I am the younger son and I’m making her dreams come true.”

It was Clement’s first major championship medal since he won the 2009 world title, having taken the silver at the Beijing Olympics the year before.