Cole Hocker has gatecrashed the most eagerly-awaited grudge match of the Paris Olympics athletics meet to claim a glorious 1500m gold for the United States.
The final had been billed as a heavyweight clash between defending Olympic champion Jakob Ingebrigtsen and reigning world champ Josh Kerr, who make little effort to hide their mutual antipathy.
But Hocker insisted afterwards he always believed his very best would be good enough for gold, even if hardly anyone else did.
The great Norwegian Ingebrigtsen set out to stamp his authority on the race from the gun on Tuesday night and stayed at the head of the field until 200m from home.
British star Kerr loomed on his outside shoulder and hit the front at the top of the final straight.
But it was 23-year-old Hocker who was fastest when it mattered most, flying home on the inside to win in an Olympic record time of three minutes 27.65 seconds, slashing more than three seconds off his personal best.
Kerr, 26, set a British record of of 3:27.79 for silver and a second American, Yared Nuguse, finished strongly for the bronze in 3:27.80, relegating the flagging Ingebrigtsen to an improbable fourth place.
The build-up to the race had been all about the rivalry between Kerr and Ingebrigtsen, who was bidding to become the first man since current World Athletics president Sebastian Coe in 1984 to successfully defend the Olympic men's 1500m title.
"We're not friends," was how Kerr described it to Letsrun.com earlier year.
"We don't hang out; we don't text. We race each other, and that's our relationship."
The 23-year-old Norwegian had previously described Kerr as "just the next guy".
On Tuesday, THE guy was most definitely Hocker.
"Winning gold was my goal this entire year," said the American.
"I wrote that down and I repeated it to myself even if I didn't believe it.
"My performances showed me that I was capable of running 3:27, whatever it took.
"I knew I was a medal contender, and I knew that if I got it right, it would be a gold medal."
Ingebrigtsen bemoaned taking the race out way too fast with a 54-second first lap, but declined to bite on being beaten home by Kerr as well as gold medallist Hocker.
"It doesn't mean that much," he said.
"I'm more disappointed that I ruined the race for myself."
The United States also provided the winner in the other big track final on Tuesday evening, with Gabby Thomas striding away to salute in the women's 200m in 21.83.
"I can't believe it, I am so excited, I feel like all of my community, my friends and family have uplifted me, so this is for them as well." Thomas said after winning gold.
"I couldn't tell you where my competitors were in that race because I blacked out and when I crossed the line, that's the only thing I remember."
Julien Alfred from St Lucia added 200m silver to the 100m gold she won three days earlier.
Alfred clocked 22.08 and American Brittany Brown took the bronze in 22.20.
Miltiadis Tentoglou from Greece (8.48m) successfully defended his Olympic long jump title, with the minor medals going to Jamaican Wayne Pinnock and Mattia Furlani from Italy.
Kenyan-born Bahraini Winfred Yavi just outlasted Uganda's Peruth Chemutai to win the women's 3000m steeplechase in an Olympic record time of 8:25.76.
