Australian duo Richie Porte and Rohan Dennis both took out overall honours after saluting on the famed stage during its most recent inclusions in the Tour, winning in 2017 and 2015 respectively.

However, Trek-Segafredo's Porte won't rest on his laurels this time around after claiming stage three in impressive fashion atop the Adelaide hill on Thursday.

The Tasmanian's powerful burst up Torrens Hill Rd saw him build a six-second general classification advantage over two-time defending champion Daryl Impey (Mitchelton-Scott) at the Tour's halfway point.

It was a significant move in Porte's bid for a second overall title after finishing runner-up a total of four times.

"Historically this has been the queen stage when it's been in the race, but there's two more stages to go before Willunga and the race is not over yet," Porte said.

"There's time bonuses on the road as well and I expect that Mitchelton will go for them."

Willunga is Porte's pet stage, which he has won in each of the last six years, and is locked in as the final stage of this year's race on Australia Day.

But the Mitchelton-Scott team has not given up hope of South African ace Impey making up ground on the leader on stages four and five.

The time bonuses on offer give Impey a huge chance to mount a challenge to Porte.

"Richie's in pole position," Mitchelton-Scott sport director Matt White said.

"It means we have to win time bonuses, doesn't it? It's doable because Daryl's improved on Willunga.

"This climb here (at Paracombe), once you have got a gap, it's easier to go on with it, whereas Willunga is a longer climb, but it's not as brutal as Paracombe.

"There's still a lot to play for and they're in pole position ... but there's a lot of wind predicted for the next couple of days, so it will make things pretty tricky, I think."

Impey, who finished sixth at Paracombe, was buoyed by teammate Simon Yates' ability to overcome a knee injury suffered in a nasty crash on Wednesday's stage two to climb onto the podium in third position on Thursday.

Impey also takes the blue sprint jersey into stage four, a 152.8km course from Norwood to Murray Bridge.

"I think we're in a great situation," Impey said.

"Obviously we'd like to be in the (ochre) jersey, but there's still lots of bonuses to come and still lots of opportunities in the race."

Australian Associated Press