Karsten Warholm set a massive world record in the men's 400 metres hurdles as the Norwegian landed gold at the Tokyo Olympics.

He became the first man to dip under 46 seconds, setting a startling time of 45.94 seconds as he fended off American Rai Benjamin, who clocked 46.17.

The top three in the race all went under 47 seconds and beat the previous Olympic record, with bronze going to Brazilian Alison dos Santos in 46.72.

Warholm was already the world record holder, setting a time of 46.70secs in Oslo at the start of July to break the previous best of 46.78 that had been held by Kevin Young since the 1992 Barcelona Olympics..

Now he has demolished his own mark, helped by being pushed all the way by Benjamin.

Warholm had a healthy lead heading into the final 150 metres but then came under pressure from the USA star over the final two barriers, the gap closing.

The 25-year-old from Ulsteinvik held his nerve and maintained his rhythm, though, sprinting away to post a record that could stand for many years to come.

All three medallists went under the previous Olympic record.

Gold in the women's long jump went to Germany's Malaika Mihambo, whose final-round effort of 7.00 metres saw her edge ahead of America Brittney Reese and NIgerian Ese Brume, the silver and bronze medallists, who both posted best leaps of 6.97m.