Innsbruck - Rohan Dennis beat favourite and defending champion Tom Dumoulin at the world championships individual time trial on Wednesday, the Australian lifting his bike aloft in triumph at the finish line.
Dennis completed the 52.1km course in 1hr 03min and 02sec at an average of 49.6 km/h despite a tough 5km climb.
Aiming to defend the title he won at Bergen in 2017, Dutchman Dumoulin finished 1min 21sec behind in a race that had been widely billed as a duel between him and Dennis.
The bronze medal went to 26-year-old Victor Campenaerts of Belgium, the 2018 European time trial champion finishing just half second adrift of the silver medal.
Dennis, a time trial specialist who has worn the leader's jersey at all three Grand Tours, said earning the right to wear the world champion rainbow jersey for a year was a dream come true.
"I have been targeting this since I was a junior and it's absolutely amazing, a dream come true," said Dennis, the first Australian crowned since Michael Rogers claimed the last of his three consecutive titles in 2005.
"I wanted to make some kind of salute on the finish line but I wasn't sure even though everyone was telling me I'd won, I wanted it to be completely sure," he said of the wait for Dumoulin to cross the line.
But he also said he knew he had a good chance from 20km out.
"At the hill, Brad McGee was coaching me," said Dennis of his coach McGee, a former professional and specialist in the discipline who was giving instructions from the team car behind him.
"He was mainly trying to keep me calm because I was so nervous about the climb.
"And as soon as I got to the top I knew I could get a time at the very least as fast as he (Dumoulin) did."
Dennis never let up, hitting speeds of almost 90 km/h on the narrow descent of the day's climb, where he overtook Spanish time-trial specialist Jonathan Castroviejo.
The tactic paid off handsomely for the Australian, who has just signed a deal to join the Bahrain team led by Italy's former Tour de France winner Vincenzo Nibali.
Adelaide native Dennis, a former holder of the hour record, has won the Australian time trial championship for the past three years.
"I'd like to thank all the folks back home in Australia, especially my wife, I'm sure she's smiling now," said Dennis.
"I'm going to relax and enjoy wearing this rainbow jersey."
Dumoulin, who won the Giro d'Italia in 2017 before claiming worlds time trial victory for the first time, looked ashen at the finish, but was smiling again by the time he got to the podium and warmly congratulated the winner.
Having pushed hard in the team event on Sunday, the Dutchman appeared not to have fully recovered from his efforts.
"I felt bad from the first kilometre," said Dumoulin, who also finished runner-up in both the Giro d'Italia and Tour de France earlier this year.
"I was feeling good on Sunday but here I understood quickly I wasn't going to win. When I got off the bike at the end I felt like and old man."
Dennis added: "I'm not that surprised because I knew he had pushed hard in the team time-trial by riding a lot at the front."
Results from the men's individual time-trial world championhips, a 52.1km run from Wattens to Innsbruck on Wednesday:
1. Rohan Dennis (AUS) 1hr 03min 02sec
(average speed: 49.6 km/h)
2. Tom Dumoulin (NED) at 1min 21sec.
3. Victor Campenaerts (BEL) 1:21.
4. Michal Kwiatkowski (POL) 2:04.
5. Nelson Oliveira (POR) 2:14.
6. Jonathan Castroviejo (ESP) 2:17.
7. Tony Martin (GER) 2:25.
8. Patrick Bevin (NZL) 2:44.
9. Vasil Kiryienka (BLR) 3:07.
10. Martin Madsen (DEN) 3:23.
11. Maximilian Schachmann (GER) 3:39.
12. Stefan Kung (SUI) 3:44.
13. Alexey Lutsenko (KAZ) 4:07.
14. Jan Barta (CZE) 4:08.
15. Joey Rosskopf (USA) 4:20.