Australia's Sam Welsford held off the fast-finishing German Phil Bauhaus to take the opening stage of Australia's Tour Down Under in his first WorldTour ride for new team BORA-Hansgrohe on Tuesday.

Welsford was perfectly positioned for the dash to the finish line in Tanunda by teammate Danny Van Poppel and prevailed by a half front wheel over last year's stage winner Bauhaus (Bahrain Victorious) with Eritera's Biniam Girmay (Intermarché-Wanty) third.

The Australian, who recently made the switch from Team DSM to BORA-Hansgrohe, leads the general classification with four seconds on Bauhaus and six seconds on Girmay.

"That was crazy, it was very hairy down the hill, lots of crashes and near misses, but the boys just kept calm, be patient and wow they did an amazing job for me today," Welsford said.

"First race with the guys and they backed me one hundred percent. That's super special, first one of the year to get a win. I'm stoked."

As the peloton sped down Menglers Hill some 13 kilometres (8 miles) to the finish line, a few riders came to grief in heavy falls.

"It was pretty fast on the downhill, we were going around those long bends, upwards of 100km an hour," he said.

"Everyone's trying to be at the front as well, it became pretty messy but I hope everyone's alright because there's still five more days left."

It was the superb teamwork by the BORA-Hansgrohe riders that made it possible for Welsford, who turns 28 this week, and he had just enough to claim the 144-kilometre (90-mile) stage of the season-opening WorldTour event staged outside of Adelaide.

"I did my best, it was the best possible result today, there's not much you do when the guy gets led out with 50 metres to go," runner-up Bauhaus said. "I am happy with the legs and it's a good result to start."

A fast-charging Girmay passed Australia's champion sprinter Caleb Ewan (Jayco-AlUla) to round out the podium.

Two-time French world road race champion Julian Alaphilippe (Soudal-QuickStep) needed a bike change during the stage and had to work his way back through the peloton before finishing 98th.

Italy's nine-time Grand Tour stage winner Elia Viviani was 32nd in the stage for Ineos Grenadiers.

"Not the best feeling for me today," he said.

The first four stages of the TDU are better suited for the sprinters before the final two weekend stages feature the testing Willunga Hill and Mt Lofty finishes.