Australian schoolboy Gout Gout scorches to 19.84sec over 200m
His blistering run was the second fastest ever by an athlete under-20 among all conditions, surpassing Usain Bolt's 19.93 in 2004 and Justin Gatlin's 19.86 in 2001.
It followed the 17-year-old storming to the 100m crown at the Australian Athletics Championships in Perth on Friday in 9.99 sec.
That too was achieved with a tailwind slightly above the permitted limit so will not make the record books.
But his rapid development is generating growing interest, with the lanky schoolboy described this year by World Athletics President Sebastian Coe as a rare talent.
"Feels really good, that's what I've been chasing," said Gout of smashing through the 20-second barrier.
Gout, who was born in Australia after his parents migrated from South Sudan, rose to prominence in December when he clocked the quickest 200m time ever by a 16-year-old of 20.04 sec, bettering Bolt's personal best at the same age.
He had to keep his nerve on Sunday after two athletes false started, including main challenger Lachlan Kennedy, before Gout exploded from the blocks and left the rest in his wake.
"I was a bit nervous," he admitted. "But in my head, I'm just keeping my composure, keeping calm, because this stuff happens, you can't really control it.
"So I just made sure I didn't false start or be unsteady, and I took off."
In other action, world championship bronze medallist Kurtis Marschall won the men's pole vault by clearing 5.71m, well short of the 6.00m he was aiming for.
Three-time Olympian Peter Bol set an Australian record in the 800m (1:43.79) while Nicola Olyslagers, who last month retained her world indoor high jump title, won the event in Perth with a leap of 2.01m.