In a solo race and almost empty stadium in Olso, the double World champion and the 2nd fastest man in history over 400m hurdles, Warholm, broke the 300m World record with blazing 33.78 seconds shaving 0.60 seconds from Great Britain's Chris Rawlinson's previous record.
"I am used to competing against myself in training! It's better to do it alone than to not do it at all." said Warholm on smashing the 300m hurdles World record.
Another Norwegian athletics star, the 19-year-old Jakob Ingebrigsten, broke the European 2000m record with 4:50.01. It was the fastest time outdoors since 2001 when Ethiopia's great Kenenisa Bekele ran 4:49.99 indoors in 2007.
Filip Ingebrigsten set a new Norwegian 1000m record with 2:16.46 shaving 0.32 seconds off the old record held by 1996 Olympic 800 champ Vebjorn Rodal.
In the men's pole vault, Sweden's Armand Duplantis cleared 5.86 for the win.
"I wanted to jump a little bit higher but I knew I wasn't in the best shape of my life right now. I know I'm rusty!" said the indoor pole vault World record holder at 6.17m.
Duplantis competed against former World indoor record-holder Renaud Lavillenie, who was jumping simultaneously from his back yard in France on a slightly shorter runaway and under windy conditions. Lavillenie cleared 5.81m breaking unofficial back yard pole vault World best.
The event was a substitute for the Oslo Diamond League meet, which was canceled because of the World-wide coronavirus pandemic. Only less than 50 athletes competed across the 13 events at the Impossible Games.