Simona Frapporti (Bepink) upstaged the big guns to win Sunday evening's final stage around a tight Adelaide street circuit, with Lauren Stephens (Tibco-SVB) and Rushlee Buchanan (New Zealand) filling out the podium.

But US road race champion Winder did just enough to preserve her overall lead and become the first international rider to win the general classification in the five-year history of the women's event.

Australian team Mitchelton-Scott had dominated since its inception, with Katrin Garfoot's 2016 triumph preceding a hat-trick of overall titles by Spratt.

The national road race champion looked set for a fourth victory when she took the ochre jersey from compatriot Chloe Hosking after winning stage two.

Spratt had never before relinquished the overall lead after claiming it on her way to a hat-trick of titles.

But Winder took control with a gutsy sprint finish on stage three - her first Tour Down Under stage win - and held onto her advantage during a tough final stage to create a slice of history.

German rising star Liane Lippert (Sunweb) was second in the general classification, with Spratt third.

"That race was pretty crazy. I used to do a lot of crit racing when I was young in the US, but it's been a bit of a while since I've done a really hard one like that," Winder said.

"Sunweb and Mitchelton are really strong teams, but we were able to pull it off and I'm really excited.

"(On Saturday) after winning the stage it was such a great feeling and I'm really excited to celebrate with my team."

Spratt was joined by compatriots Australian trio Chloe Hosking (Rally Cycling), Jessica Pratt (Canyon-SRAM) and Peta Mullens (Roxsolt Attaquer) in the general classification top 10.

While disappointed not to win, Spratt said she was proud to be on the podium.

"My reign at the Tour Down Under had to end at some point," Spratt said.

"I can't fault the team this week, they all rode really well.

"There wasn't much more that we could have changed, we were just beaten by a stronger rider, especially on (Saturday's) stage.

"It was a different Tour this year, it all came down to bonus seconds.

"That made it quite exciting and it put me out of my comfort zone today too."

Australian Associated Press