Sitting at the front of the peloton heading into the final two-kilometre, category 1 climb into Paracombe, Porte broke away to open up a sizeable gap on Simon Yates and Rob Power before crossing the line in 3:14:09 with a five-second gap on the next eight riders.

The result gives Hadspen's Trek Segafredo rider a six-second buffer on South Africa's two-time defending champion Daryl Impey with Porte's pet stage six, Willunga Hill, still to come.

ELSEWHERE IN SPORT

"The team were fantastic firstly so I have to take my cap off to those boys," Porte told Channel Seven post-race.

"They put all their faith in me today and did a really good job in controlling it.

"It felt good at the bottom of the climb and I got a bit of a gap there and I had a professional teammate - Juan Pedro Lopez was really good.

"It was a shame it was such a headwind there in the final because I think we could have done some real damage."

The Tour Down Under's 2017 winner and four-time second-place finisher, Porte is in a strong position to claim a second TDU title if history is anything to go by.

Both he and Rohan Dennis won the stage and the tour when Paracombe's Torrens Hill Road finish featured in the 2017 and 2015 editions of the TDU, although the 34-year-old insisted this year's race was far from over.

Porte said Mitchelton-Scot's Impey - the only rider to ever win the event two years running - remained the man to beat.

"I think back to 2015 when Cadel Evans and I were looking at each other and Rohan came from behind and smacked us and won the stage and won the tour, so to win again this year is a sweet feeling," he said.

"Daryl's still the man to beat I think with the bonus seconds on the road.

"To take another victory on a stage like this is a great feeling so I'm going to savour that firstly."

Friday's fourth stage is a 152.8km trek from Norwood to Murray Bridge.