Norway's Karsten Warholm shattered his own world record to win the men’s 400m hurdles at the Olympics.

The new champion only broke the 29-year-old record last month, but clocked 45.94 seconds in Tokyo on Tuesday.

He took almost a second off his previous world best of 46.70 he set in Oslo at the start of July.

He finished ahead of the USA’s Rai Benjamin (46.17) and Brazil’s Alison Dos Santos (46.72), with both coming inside Kevin Young’s time of 46.78 the American set nearly 30 years ago.

"This is probably one of the few moments where it's very difficult to find the right words," he told RTÉ Sport afterwards.

"What I can say for sure is that this moment is very special for me and to be able to win this race is something that is just a dream.

"Me and my coach [Leif Olav Alnes], all the work we've been putting in, we really deserve this.

"Going in there I don't think too much. This is all my training hours going into the race. I work it out in my head. It's a lot of pressure going into the race. I told myself going out there that it was going to be very special in the end - that's when the race is going to be determined.

"Coming off the last hurdle I knew I could win if I fought with my life. For me winning is everything and it's very special to get this gold medal."

Asked was he surprised how fast he had run he said: "Yeah man! 45 - that's very special."

Reflecting on what might come next, Warholm added: "I hope I can get a beer.

"Everything has been about this race. I've been making tough choices. I've been doing everything I can just to be in the perfect shape here and now I feel like I deserve to relax a bit and enjoy my moment."

Warholm led from the start, but Benjamin looked like he was about to reel him in with 90 metres to go.

Yet Warholm found an extra gear to pull away in the final 60 metres and add the Olympic title to his two World Championship crowns and European gold.