The Team INEOS rider won his home stage race in 2017 and is now well placed for a second title at the International Cycling Union World Tour curtain raiser.

He powered up the steep hill to the finish line after a 131-kilometre ride from Unley to Paracombe, in a winning time of 3 hours 14min 9sec.

"The team was fantastic, firstly," said Porte.

"They put all their faith in me today. 

"They did a really good job at controlling it. 

"I felt good at the bottom of the climb and I got a bit of a gap there. 

"My neo-professional team mate Juan Lopez was really good and it was a shame it was such a headwind in the final.

"I think we could have done some real damage."

Porte rode home five seconds quicker than Australian Team Sunweb cyclist Robert Power, who finished second, while Britain's 2018 Vuelta a España champion Simon Yates, riding for Mitchelton-Scott, was given the same time in third.

With the time bonuses for the stage victory, Porte claimed the ochre jersey for the general classification lead with an overall time of 10:10.24.

He has a six-second advantage over South Africa's Daryl Impey, who has won the last two editions of the Tour Down Under.

Impey ended sixth today on the same time as Power and Yates and remains a threat due to his ability to gain bonus time during the sprint sections.

Australia's Caleb Ewan, who won stage two to claim the ochre jersey yesterday, fell away at the start of the final climb and finished 61st.

He is now 55th overall and more than two minutes behind.

Tomorrow's fourth stage of six covers 152.8km from Norwood to Murray Bridge.