Great Britain's Josh Kerr broke Mo Farah's world two-mile indoor record as he won at the Millrose Games in New York.
World 1500m gold medallist Kerr ran eight minutes 0.67 seconds to beat Farah's mark of 8:03.40 from 2015.
"It was always going to be really tough, small margins," Kerr, 26, said.
Kerr's fellow Scot Laura Muir set a new British indoor record as she won the women's two-mile race after Ethiopia's Medina Eisa was disqualified.
Eisa was first home in New York but cut in too early on the opening lap.
Muir, 30, was promoted from second to first after finishing in nine minutes and 4.84 seconds.
The Olympic 1500m silver medallist, who won the Wanamaker Mile at last year's Millrose Games, will look to win the world indoor title in Glasgow next month.
In the men's two-mile race, Kerr charged at the finish to defeat Grant Fisher, who set an American national record of 8:03.62.
Farah set the previous world indoor best at Birmingham nine years ago.
"I had to roll with the punches at the start of my career - pretty good but not world class," said Kerr.
"And then to be world class and now world champion... I'm having fun with it, creating big goals to get myself out the door and prove I'm not all talk."
Devynne Charlton of the Bahamas set a new world record in the women's 60m hurdles.
Charlton clocked 7.67 seconds in the hurdles to shave 0.01 off the previous world record set by Sweden's Susanna Kallur 16 years ago.