(CNN)Australia's Rohan Dennis set a pace as blisteringly hot as the sweltering heatwave in the Dutch city of Utrecht to don the first yellow jersey of the 2015 Tour de France with a record-breaking ride.
Tour de France 2015: Rohan Dennis dons yellow in Utrecht heatwave
The BMC rider upset more fancied contenders to clock 14 minutes 56 seconds for the 13.8km individual time trial, his average speed of 55.45kph, the fastest in Tour history for a stage of this type.
He finished five seconds clear of former world time trial champion Tony Martin (Etixx-Quick-Step), with another famed performer against the clock, Fabian Cancellara (Trek Factory Racing) in third, a further second adrift.
A bitterly disappointed Martin complained that the heat, topping 30 degrees Centigrade, (86 degrees Fahrenheit) and a lack of breeze with so many spectators lining the streets of the built up city, had compromised his effort.
Dennis, an earlier starter, had set a time which proved unbeatable as the temperatures soared.
But his performances this year had marked out the 25-year-old as a dangerous outsider for the first stage.
He won his native Tour Down Under and also set a world hour record on the track, his mark subsequently between by British pair Alex Dowsett and current holder Bradley Wiggins.
For the contenders for the overall victory come Paris in three weeks time, the time trial may well have been represented a tiny fraction of the 3,360km awaiting them, but valuable time could be lost.
Defending champion Vincenzo Nibal (Astana) fared the best, 43 seconds down on Dennis, but seven seconds ahead of 2013 champion Chris Froome (Team Sky), the second Briton after Wiggins in 2012 to win the Tour.
Giro d'Italia winner Alberto Contador (Tinkoff-Saxo) was a further eight seconds adrift of Nibali, who has an 18 seconds advantage over Colombian Nairo Quintana (Movistar).
Quintana will be looking to press his credentials in the seven mountain stages, five of them summit finishes, where the Tour is likely to be decided.
The nine-strong squads must also compete in a team time trial over 28km next weekend, but otherwise the 102nd edition of the Tour is likely to heavily favor climbing specialists.
Dennis, who has no pretensions to overall victory, is the seventh Australian to wear the yellow jersey and will take his place in the peloton for Sunday's largely flat 166km leg from Utrecht to Zelande where bunch sprint specialists such as Mark Cavendish of Britain are expected to come to the fore.
Saturday's hot conditions are considered unusual for the usually temperate Netherlands, where after five days over over 25 degrees C, with three of them being over 30 degrees, an official heatwave is declared for health reasons.