Defending champion Daryl Impey took the lead in the Tour Down Under from chief rival Richie Porte as Italy's Giacomo Nizzolo won Saturday's fifth stage in a bunch sprint finish.
South Africa's Impey will take a two-second advantage over Porte into Sunday's final stage up the gruelling Willunga Hill as he chases his third straight victory in the UCI season opener.
The Mitchelton-Scott rider finished second and first at two intermediate sprints and collected enough time bonuses to supplant overnight race leader Porte of Trek-Segafredo.
Impey's narrow but psychological lead will be important as he attempts to hold back the Australian, who has won the last six stages up the torturous three-kilometre climb to the tour's finish.
"It's fantastic to lead the race going into Willunga," Impey said.
"The whole week we've been trying to get into the lead here and put myself in a position tomorrow to beat Richie.
"I'm two seconds up, I don't know if it's enough, but we've given ourselves every chance to win this bike race and it's all up to tomorrow."
Porte, the 2017 winner and four-time runner-up, is a noted Grand Tour climber, and knows the simple equation to win his second TDU title.
"It's not a massive deficit tomorrow, but it will be hard," he said.
"If we can win the stage, we can win the race. We are going to have to have guys up there tomorrow. I was a little isolated today, so hopefully tomorrow the boys are on again."
Nizzolo scored the first win for the newly branded NTT Pro Cycling thanks to positioning by his teammates, leaving him poised for a final charge into Victor Harbour where he easily fended off all challengers.
Fellow Italian Simone Consonni of Cofidis was second, ahead of Irish stage one winner Sam Bennett for Deceuninck-QuickStep.
"I can't thank my teammates enough. They did a great job," Nizzolo said.
"That was the plan, that if I was a bit off they would come back and wait for me on the climb.
"They did it perfectly and I was in the perfect place and I just put everything on the pedals I had. It worked in the end, so I'm so happy."
Defending champion Daryl Impey will take a two-second advantage over Richie Porte into Sunday's final stage