Swift also won a stage at last year's Tour de Picardie
Ben Swift won the second stage of the Tour Down Under after a chaotic finale to give Team Sky their first victory of the 2011 season.
The Yorkshireman, 23, was preparing to lead out Chris Sutton but when his team-mate was involved in a crash 4km from the line, Swift powered home.
RadioShack's Robbie McEwen was second with Rabobank's Graeme Brown third.
Sky rider Geraint Thomas also took a tumble in the 146km stage, falling close to the finish line in Mannum.
"I couldn't believe that G [Geraint] had fallen because he was right there with 200m to go," said Swift.
"I've just seen him now and thankfully he is all right, but CJ [Sutton] is not so great and has a deep cut on his knee. He's a tough guy and I'm confident he will be able to battle on."
Sprinter Mark Cavendish, who rides for HTC-Highroad, also crashed in the closing stages of the race but was able to avoid serious injury and crossed the line three minutes, 47 seconds behind Swift.
Seven-time Tour de France champion Lance Armstrong, who is taking part in his final overseas event, finished in 42nd.
McEwan leads the overall classification, with Matthew Goss (HTC) and Swift tied with him.
Meanwhile, Swift could now be handed the task of leading the team for the rest of the race, with Sutton and Greg Henderson both struggling after a number of recent falls.
"That would be a massive honour and I'd take it, for sure," said Swift. "That said, I don't mind dropping back and resuming my original lead-out role either. Whatever I have to do for the team, I'll do it."
Thursday's third stage will take the peloton from Unley to Stirling.
"If I've got good legs, tomorrow's stage could be one that suits me but it looks set to be a really tough one because the temperatures are due to rise to around 36 degrees," added Swift. "We'll just have to see how it goes."