A desperate sprint for second place by Katrin Garfoot means the Orica-AIS cyclist has retained the overall lead in the Santos Women's Tour.
Her teammate Lizzie Williams won Monday's 100.8km third stage in blistering heat.
Garfoot is in a four-way tie for the overall lead, equal on time with fellow Australian Lauren Kitchen (Hitec), American Shelley Olds (Cyclance) and British rider Dani King (Wiggle Hi5).
The tour will come down to Tuesday afternoon's last stage, a circuit race at Victoria Park in the Adelaide parklands.
"I had to make sure I outsprinted Lauren to keep the jersey," Garfoot said.
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"I don't know how I did it because I'm not a sprinter but it was good for us. We're really happy."
Orica-AIS rider Amanda Spratt made a solo break during the Barossa stage, which started and finished in Lyndoch.
Her effort meant Williams and Garfoot could conserve energy in the chase group as other riders, including Kitchen, led the chase.
After Spratt was caught, Williams attacked by herself with four kilometres to the finish.
"Spratty was just a workhorse out the front, dangling like a rabbit," Williams said.
"She allowed us to sit on the whole time and ultimately I had the energy to go with about four kilometres to go. That's teamwork."
An exhausted Williams won by 19 seconds and Garfoot led home Kitchen, Olds and King in a four-way sprint for second.
