The 28-year-old BMC rider, who was considered one of the favourites prior to the start of the competition, began his race second from last and blitzed the course, maintaining an average speed of 49.6 kilometres per hour.

His imperious display meant that as he crossed the line in 1 hour 3min and 2.57sec he knew he would not be caught, even though Dutchman Dumoulin remained out on the course in the Austrian city.

The Team Sunweb rider eventually finished 81 seconds behind the winner for silver.

Third place was taken by Belgium's Victor Campenaerts who finished 1:21.62 behind for Lotto-Soudal.

Dennis passed through the first time check after 16.6km of the 52.2km course with a nine second lead and merely extended that advantage as the race progressed.

The defining feature of the course, the Gnandenwald climb, saw Dennis not just catch but pass Spain's Jonathan Castroviejo ahead, and by the top the Australian held a lead of more than a minute over Dumoulin.

By that point his lead was so great Dennis effectively only needed to stay upright to seal the win, but he continued attacking regardless, eventually catching 2015 world champion Vasil Kiryienka of Belarus as well.

A silver medallist at under-23 level in 2012, Dennis has endured his share of ill fortune at championship individual time trials over the years, most notably when damaged aero bars denied him a medal at the Rio 2016 Olympics.

No similar misfortune affected him today, however.

"I was considering a bit of a victory salute, but I wanted to make sure [of the win]," he said afterwards.

"You're never sure until Tom [Dumoulin] does cross the line."

The junior road races will be held tomorrow.