The defending Tour Down Under champion withstood a clear two-rider breakaway on stage four after his BMC teammates on the category 1, 5.8km climb prevented any attacks with a high-pace contest until the summit.

The Hadspen cyclist, who took out maximum king-of-the-mountain points on Friday, was forced to launch a counterattack on a group of challenging riders.

Porte had to chase down world champion Peter Sagan (Bora-hansgrohe) to bring the group back together.

He led the group with under 1km to go before Sagan took the stage win in the reduced bunch sprint, as Porte followed behind in the group to finish with the same time.

Porte sounded somewhat indifferent amid the mercury hovering around 43 degrees.

“No one really wanted to take the lead, but I don’t think it was up to me,” Porte said after the stage. “I didn’t feel good today – I felt empty, a little bit sick overnight.

“I had a pretty rough day. I’m not in a bad position.”

The 32-year-old now sits 14 seconds back ahead of the penultimate stage, which finishes with the ascent of Willunga Hill – a stage that Porte has claimed for the last four consecutive years.

“It was nice to be there with a selection because over those rollercoaster sections, I think the stronger guys were at the front,” Porte said. 

“But we’ll see how Sagan goes tomorrow. Norton Summit is not a terribly hard climb. Obviously, today was a bit harder with the heat.

“It was such a hot day and it kind of felt like you were climbing at altitude there.

“Hopefully, tomorrow we can recover.”

He has now ominously settled into 20^th overall – two positions ahead of Hobart’s Richard Earle – heading into Porte’s notoriously strongest rides of the tour.

Campbell Town’s Will Clarke sits back in 66^th and Hobart sprinter Scott Bowden is 122^nd overall.