Impey makes his move in Tour Down Under

Adelaide - South Africa's Daryl Impey surged into contention to defend his Tour Down Under title with a thrilling win ahead of race leader Patrick Bevin in Adelaide on Friday.

The Mitchelton-Scott rider claimed the fourth stage to move to second overall just seven seconds behind New Zealand's Bevin (CCC Team) with two stages left in the UCI season-opening world tour event in South Australia.

Impey gave his hopes of becoming the first rider to go back-to-back in the race's 21-year history a massive boost with his stage victory.

Astana's Leon Luis Sanchez went early but was caught by Impey and Bevin in the last 20 metres to finish third on the 129.2-kilometre (80-mile) stage through the Adelaide Hills from Unley to Campbelltown.

"I'm so stoked to have done something like this, it's so special," Impey said.

"I knew if I lined up Paddy Bevin, I'd have a good shot at winning, so I'm super-happy to win today."

The stage featured the challenging Corkscrew Road ascent as a final test some six kilometres from the finish.

Wout Poels (Team Sky), George Bennett (Team Jumbo-Visma), Richie Porte(Trek-Segafredo) and Michael Woods (EF-Education First) attacked on the final climb.

But they were caught by the chasing bunch, led by Impey and Bevin, on the descent resulting in an exciting 20-rider finish.

Poels, Bennett, Porte and Woods announced themselves as the top climbers ahead of Sunday's challenging final stage at Willunga, where the Tour winner will be anointed.

"It's (points lead) still not a huge buffer," Bevin said.

"Those four (Porte, Bennett, Woods and Poels) showed themselves as the best pure climbers in this race, but this race fortunately is about being an all-rounder.

"Basically you've got to sprint better than the climbers and climb better than the sprinters."

Australia's Jason Lea (UniSA-Australia) retained the King of the Mountain jersey after stage four from Bennett and Italy's Manuele Boaro (Astana Pro Team).

Former triple world champion Peter Sagan (BORA-hansgrohe) fell back in race contention following Thursday's stage win and finished 29th in Friday's leg to be 20th overall.

Bevin took over the sprint leader's jersey by 12 points from Sagan and Sanchez.

Saturday's Stage 5 over 149.5km begins in Glenelg and finishes in Strathalbyn.

Results after the 129.2km fourth stage of the UCI Tour Down Under from Unley to Campbelltown in South Australia on Friday:

Stage

1. Daryl Impey (RSA/Mitchelton-SCOTT) 3hr 3min 27sec

2. Patrick Bevin (NZL/CCC Team) same time

3. Luis Leon Sanchez (ESP/Astana Pro Team) s.t.

4. Ruben Guerrero (POR/Team Katusha Alpecin) s.t.

5. Ruben Fernandez (ESP/Movistar Team) s.t.

6. George Bennett (NZL/Team Jumbo Visma) s.t.

7. Diego Ulissi (ITA/UAE Team Emirates) s.t.

8. Michael Woods (CAN/EF Education First Pro Cycling) s.t.