Touted as one of the stand-out events of the 10-day track and field programme at the Olympic Stadium, the cream of a very good hurdling crop did not fail to deliver in a thrilling race despite stifling midday heat and humidity in Tokyo.
Warholm clocked a remarkable 45.94 seconds, pulverising his previous world best of 46.70sec. To put that performance into perspective, only four runners in history have even clocked sub-47sec times, let alone sub-46.
American arch-rival Rai Benjamin won silver in 46.17sec, with Brazil's Alison Dos Santos claiming bronze in 46.72, both regional records that also smashed their previous personal bests.
As the Norwegian, with minimum upper body movement as he negotiated the early hurdles, hit the final 200 metres well ahead of the field, the question was whether he could keep his rhythm and pace.
Benjamin had not given up hope and pushed down the home straight, coming almost neck-and-neck on the 10th and last hurdle.
Warholm, teeth gritted and head flailing, looked like he might tie up to hand the American victory.
But from somewhere, the Norwegian two-time world champion dug deep and found just enough energy for an extra spurt that saw him surge through the line.
Eyes bulging at the world record time flashed up on the big screen, Warholm roared and spontaneously ripped open his shirt amid gasps from sparse pockets of fellow athletes and team officials at a stadium empty of spectators because of coronavirus rules.
There were national records for British Virgin Islands' Kyron McMaster in fourth, Turkey's Cuban-born 2017 world silver medallist Yasmani Copello in sixth and Estonian Rasmus Magi in seventh.
Qatar's 2019 world bronze medallist Abderrahman Samba, one of the four runners to have dipped under 47 seconds in his career, was fifth in a season's best of 47.12.
The result caps a remarkable renaissance of the event, both for men and women.
The breakthrough for Warholm came at the Oslo Diamond League last month.
On his home track of Oslo on July 1, the 25-year-old timed 46.70sec to break Kevin Young's long-standing mark set at the 1992 Barcelona Olympics, almost four years before he was born.
That result had come just days after Benjamin ran a world-leading 46.83sec to win the US Olympic trials.
There were similar upheavals in the women's 400m hurdles when American Sydney McLaughlin became the first woman to dip below the 52-second mark.
McLaughlin clocked 51.90sec to also win the US trials last month after a superb tactical race against reigning Olympic and world champion Dalilah Muhammad.
The women's final, featuring McLauglin and Muhammad, is set up nicely for Wednesday.