Two Australians well known to the Tour Down Under have masterminded Tobias Lund Andresen snatching the win from the stage-one favourites.
The Dane held off Australian Sam Welsford and fellow sprint ace Matthew Brennan at the high-speed finish on Wednesday in the Barossa town of Tanunda.
That also gave Lund Andresen the overall lead. It is the ideal start for him at the Decathlon CMA CGM team after transferring from Team Picnic PostNL.
A year ago, Andresen won the Surf Coast Classic at Torquay near Geelong, also beating Welsford.
Australians Luke Roberts and Mark Renshaw, veterans of the Santos Tour as riders and team bosses, are in charge of Decathlon CMA CGM this week and they rode superbly to set up Andresen for the win.
"I was quite sure we could win this one," Roberts told AAP.
"Obviously with Welsford having won here (in the Barossa) the last couple of years (and) Brennan - they're two of the top favourites. They needed to take responsibility for the race.
"We could focus on our sprint final.
"I knew the combination of them (Lund Andresen and his leadout rider Tord Gudmestad), they had the ability to win on a stage like this. They set it up perfectly.
"To start the season off in my home town (Adelaide) and straight up with a victory, it's fantastic."
Lund Andresen paid tribute to Roberts and Renshaw seconds after the win.
"This feels amazing. I can't remember the last time I felt like this," Andresen told the Seven Network.
"This is unbelievable ... my teammates did an incredible job.
"You need to be a little bit stupid to be a sprinter and enjoy this kind of finish, but our plan was so good from Mark and Luke, the preparation we had."
Welsford, who was third behind Brennan, was caught on the barriers and told the Seven Network he was "kicking himself" after he and his Ineos Grenadiers teammates had done a lot right in the high-speed run to the finish.
"The boys rode really well today, hats off to my team," Welsford said.
"No one else gave us much help. We kind of got a little bit swamped, just on the finish here.
"We did a really good job taking front around the last corner ... I got stuck on the barriers there, I couldn't get out, and I'm just kicking myself.
"I had to stop pedalling 20m from the line - it is what it is."
Likewise, Brennan was left lamenting small errors from Visma-Lease A Bike as he finished runner-up at Tanunda for the second year in a row.
"We made one little mistake, but to be honest the whole day was perfect and that's exactly what you want. It's really good things for the next races ahead," Brennan said.
Ineos Grenadiers and Visma-Lease A Bike drove a fierce pace at the front of the peloton in the 120.6km stage.
The temperature was in the high 20s on Wednesday, ahead of the blast of heat that will hit the Tour at the end of the week.
It will reach the low 40s for Saturday's key stage, featuring three laps of the iconic Willunga Hill climb.
Dutch cyclist Max van der Meulen was the first race casualty on Wednesday, taken to hospital for observation after he crashed early in the stage.
German rider Marius Mayrhofer (Tudor Pro Cycling) also crashed out inside the last 50km.
Andresen took the overall lead from Welsford's English teammate Sam Watson, who won Tuesday's prologue time trial.
The overall lead is certain to change again in Thursday's tough second stage, where the GC contenders will show their hands on the two climbs up Corkscrew Rd.
Meanwhile, Canadian Maggie Coles-Lyster (Human Powered Health) won the women's one-day race, which was held on a circuit at Tanunda after the men's stage ended.
Swiss star Noemi Ruegg (EF Education Oatly), who successfully defended her women's Tour title on Monday, finished second in the bunch finish to the 94.2km race.
Poland's Marta Lach (SD Worx-Protime) was third ahead of Australian Alex Manly (AG Insurance-Soudal).
