Last updated on .From the section Athletics

Welshman Dai Greene vowed to add 2012 Olympic gold to the World Championships 400m hurdles title he won on Thursday.

Greene, 25, ran a scintillating race in Daegu to deliver Britain's first gold of the championships - and fifth medal in all - in a time of 48.26 seconds.

"I can't settle for anything else now I suppose," Greene told BBC Sport of his London 2012 gold medal aspirations.

"I don't think it's really sunk in to be honest. I'm very proud. This was my aim throughout the year."

Britain's Greene added: "I'm just very happy to have achieved it. But like I say, it hasn't really sunk in yet.

Greene held his nerve after two aborted starts, the athletes having been called back to their blocks after a first faulty start and then told to stand up again before the race got under way.

The Welshman came past Puerto Rico's Javier Culson off the final barrier, Culson taking silver in a time of 48.44 and South Africa's LJ van Zyl winning bronze in 48.80.

quote I saw Hannah England's performance and saw her running around with the flag, and thought I had to get a piece of that action

"Coming off the bend I thought, 'I've set up the race quite poorly here', so I had to dig deep at the end," he added.

"I'm a fighter and I'm strong and I showed my determination at the end and my will to win and I'm just happy to come away with a win."

Greene now has the world, European and Commonwealth titles in the 400m hurdles to his name.

"I've been working so hard for this for a number of years. I always believed I could make it but I had to dig deep to pull it out," he said.

"I do get a bit nervous but I seem to be able to handle it better than the rest.

"I saw Hannah England's performance and saw her running around with the flag, and thought I had to get a piece of that action."

It was Britain's fifth medal of the championships and is a big boost to the GB team which makes head coach Charles van Commenee's overall target of "seven to eight" much more likely than it had appeared midway through the week.

Jesse Williams joined US team-mates Lashinda Demus, who won the women's 400m hurdles, and Jennifer Simpson, 1500m champion, on top of the podium as he won high jump gold from Russia's Aleksey Dmitrik and Trevor Barry of the Bahamas. His first-time clearance at 2.35m was enough to take the title, with pre-event favourite Ivan Ukhov out of the medals.

Kenya's Ezekiel Kemboi defended his men's 3,000m steeplechase world title, producing a memorable celebratory dance as he slowed to cross the line in a time of 8:14.85, comfortably ahead of compatriot Brimin Kipruto (8:16.05).

Kemboi's team-mate Asbel Kiprop confirmed his position as favourite for the men's 1500m with a classy qualification, while Norway's Olympic and world champion Andreas Thorkildsen was an uncharacteristic fourth as he came through javelin qualifying.