Zharnel Hughes smashed the 30-year-old British 200m record by clocking 19.73 seconds in front of a sell-out crowd at the London Diamond League.
The 28-year-old shaved 0.21 seconds off the previous mark of 19.94, set by John Regis at the World Championships in 1993, in finishing third at London Stadium.
His latest feat was witnessed by around 50,000 spectators and comes just a month after he broke Linford Christie's 100m record when he ran 9.83 seconds in New York.
American world 200m champion Noah Lyles, who on Saturday backed Hughes for the British record, triumphed in 19.47 secs, while Letsile Tebogo of Botswana was second in 19.50 secs.
Hughes claimed he had earlier forecasted his record-breaking time.
"I did it again - I predicted it," he said. "I wrote down that exact time this morning, at about 9.30am.
"I wanted to get the British record here on home soil and I did it.
"I don't care about winning as long as I execute the time that my coach wanted and get the British record."
Hughes looked like a genuine threat to Lyles before his rival pulled clear on the home straight.
"We've got things I can work on but I executed my race and that was to get to 60m as fast as possible then just maintain from there," he continued.
"I think Noah was playing off me slightly - he was ready to chase me down."
Hughes' exploits were followed by Jemma Reekie claiming glory in the women's 800m.
After Olympic silver medallist Keely Hodgkinson withdrew from the race due to illness, Reekie crossed the line in a meet record 1:57.30 to lay down a marker ahead of next month's World Championships in Budapest.
"I was disappointed Keely wasn't in the race but I tried to just focus on myself," said Reekie.
"I'm in the best place I could be happiness and training-wise, so I think there's nothing to lose in Budapest now - I'll be going there to chase a medal."
Meanwhile, Dina Asher-Smith underlined her credentials by finishing second in the women's 100m with a season's best.
The former 200m world champion pushed Jamaican Shericka Jackson into third by clocking 10.85 secs, 0.10 secs behind Marie-Josee Ta Lou of Ivory Coast, while compatriot Daryll Neita finished fourth.
Earlier, both British teams claimed podium places in the men's 4x100m relay.
Second-placed quartet Jeremiah Azu, Hughes, Jona Efoloko and Tommy Ramdhan finished in 38 secs, 0.2 secs adrift of the world-leading time of 37.8 secs posted by winners Japan, with compatriots Adam Gemili, Oliver Bromby, Richard Kilty and Joe Ferguson 0.14 secs further back.
"I think we can go out and win it in Budapest, 100 per cent," said Azu. "We know the GB guys can roll 37 low so it would be amazing to be part of that."
Britons Annie Tagoe, Imani Lansiquot, Bianca Williams and Kristal Awuah were third in the women's relay behind the Netherlands and the United States.
Scottish runner Neil Gourley claimed bronze position in the men's 1500m in a personal best time of 3:30.60, while Aimee Pratt came third in the women's 3000m steeplechase in a season's best 9:16.10.
However, there was frustration for Olympic bronze medallist Holly Bradshaw, who withdrew from the women's pole vault due to a minor injury.
In the Para-athletics events, Sammi Kinghorn got the better of fellow Briton Hannah Cockroft in the mixed-class women's 800m wheelchair race.
The T53 100m world champion triumphed in 1:46.57, with seven-time T34 Paralympic champion Cockroft 0.54 secs off the pace in third.
Britain's Kevin Santos set a national record of 10.78 secs to win the men's 100m ambulant race.
