Sarah Gigante has won her first Tour Down Under title with a blistering solo attack on the iconic Willunga Hill climb.

The 23-year-old Australian launched a solo attack with 2km left in Sunday's third and final stage, winning at the summit by 20 seconds and securing the overall title.

It confirms the Tokyo Olympian is back after two difficult years of injuries and illness. 

Gigante was in tears at the finish line as she celebrated with her mother and brother.

"It's pretty tough when you're 23 and lots of people think you're washing up," she told Channel Seven.

"It was so hard to keep believing in myself, but I did."

Gigante also moved to the AG Insurance-Soudal team in the off-season and that has paid immediate dividends, with her teammates giving her faultless support.

Gigante was always going to be the rider to watch on the 3km Willunga Climb that was the key feature in this edition of the women's Santos Tour.

As the 93.4km stage from Adelaide went along the coast before the Willunga climb, rivals tried to use the windy conditions to unseat Gigante from the peloton with echelon riding.

But Gigante was placed perfectly for the final climb in a big front group and she won with a storming ride up Willunga.

Dutch rider Nienke Vinke (DSM-Firmenich) finished second, 20 seconds behind Gigante and Australian Neve Bradbury (Canyon-SRAM) was at 33 seconds for third.

Three-time Tour Down Under winner Amanda Spratt (Lidl-Trek) was fourth at 37 seconds, while Danish overnight leader Cecilie Uttrup Ludwig blew on the climb and finished ninth at one minute two seconds.

Vinke and Bradbury also finished second and third overall.

Gigante also won on Willunga three years ago when the tour became the domestic-only Festival Of Cycling because of COVID-19.

This is the first year that Willunga, long a feature of the men's tour, has been used for the women's international race in and around Adelaide.

Newly-crowned Australian road champion Ruby Roseman-Gannon won the first intermediate sprint at 49.1km, making her equal overall leader with Uttrup Ludwig.

Roseman-Gannon then placed third in the second sprint, but Polish rider Dominika Wlodarczyk won it.

That meant Roseman-Gannon and Wlodarczyk had a one-second overall lead over Uttrup Ludwig.

But the race was always going to be decided on the Willunga climb.

Just before the second sprint at coastal Aldinga, there was near-disaster when a dog strayed onto the side of the road.

But the peloton was attentive and there were no crashes.

AAP