Budapest: The United States won both 4x100 metres relays at the World Championships on Saturday as their individual superstars Noah Lyles and Sha'Carrie Richardson ran anchor legs to complete triple medal weeks.
Lyles added the relay gold to his sprint double while Richardson had already claimed 100m gold and bronze in the 200m.
"It's sensational, amazing. You can't do better. It's out of control," Lyles said. "I love team USA because everybody is coming here thinking 'I'm going to win'. We're able to put that into a team effort and then we're unstoppable."
It was a glorious end to the night for the sport's superpower after the earlier disappointment of seeing their highly-favoured 4x400m women's team disqualified following a baton failure in the semi-finals.
Despite their rich depth, the US men had not won an Olympic final since 2000 and had just one gold from the last seven World Championships amid a series of fumbles and disqualifications.
But they were almost faultless on Saturday as Christian Coleman, Fred Kerley, Brandon Carnes and Lyles won in 37.38.
"We all know we're fast," said Lyles. "We don't have to worry about whether we're going to win. It's just about getting the stick around and trusting each other. It's fun to do this."
Olympic champions Italy, with Tokyo individual gold medallist Lamont Marcell Jacobs on the second leg, took silver with 37.62. Jamaica finished strongly to edge out Britain for bronze in 37.76.
Richardson and Gabby Thomas were added to the women's team alongside Tamari Davis and Twanisha Terry and the foursome were superb in running a championship record time of 41.03 seconds.
"Dreams like this come true," Richardson said. "I'm just glad that I was able to be here for my first world championship and to do the things I've been working on all season."
The much-anticipated last-leg showdown between Richardson and Jamaica's 200m champion Shericka Jackson turned into a non-event as the American collected the baton a metre clear and was never challenged.
Jamaica took silver in 41.21 while Britain claimed bronze with 41.97.
The victory edged the US further ahead in their great women's sprint relay rivalry with Jamaica, having now won six to Jamaica’s four of the last 10 World Championships.
Baton mishaps are common in the shorter relay, less so in the 4x400, but the US women paid a heavy price for theirs on Saturday.
They had won seven of the last eight World Championships and the last seven Olympic golds but were trailing an impressive British team after three legs when Alexis Holmes initially failed to collect the baton from Quanera Hayes.
By the time Holmes eventually got hold of it she appeared to have gone beyond the "blue box" while Hayes had stepped off the track and though Holmes recovered to finish second behind Britain in the heat, the US were disqualified.
Jamaica and Canada were the fastest into Sunday's final.
The similarly dominant US, men, who have won eight of the last nine world titles and four of the last five Olympics, also progressed in a heat where India ran an Asian record 2:59.05 - the first time they have cracked three minutes.
Jamaica, perennial global silver medallists in recent years, won the second heat but they are likely to need another mishap to see anything but a US victory on Sunday, the last night of the championships.