The Mitchelton-Scott rider beat Bevin just before the line in Campbelltown after a reduced peloton had brought back a select group of star-studded climbers just in time for a sprint finish.
>> Struggling to get to the shops? Try 6 issues of Cycling Weekly magazine for just £6 delivered to your door <<
Bevin’s second-place earns him six bonus seconds and he increases his lead in the ochre jersey to seven seconds from Impey. Third-place on the stage Luis Leon Sanchez (Astana) sits 19 seconds adrift of the New Zealander.
It had looked like one of the pre-race favourites would come out on top in the undulating stage, with Wout Poels (Team Sky), George Bennett (Team Jumbo-Visma), Richie Porte (Trek-Segafredo) and Michael Woods (EF-Education First) attacking on the final climb.
But they were eventually caught and when it came down to the sprint it was the South African champion Impey who had the fastest legs.
How it happened
Riders would have appreciated the drop in temperature at the beginning of the stage, and once they got going a breakaway of six formed. It consisted of Thomas de Gendt (Lotto-Soudal), Hermann Pernsteiner (Bahrain-Merida), Miles Scotson (Groupama-FDJ), Benoit Cosnefroy (AG2R La Mondiale), Jasha Sütterlin (Movistar) and Nicholas White (UniSA-Australia).
The group enjoyed a lead of over five minutes, but their advantage dipped to one minute with 20km remaining. It was then that local rider Scotson and breakaway specialist De Gendt jumped clear of their escapees, hoping to extend their time gap on the 10km downhill on Gorge Road. The six, however, were soon back together.
Fifteen kilometres from the finish and Scotson tried his fortune again, setting an incessant pace. Only Pernsteiner and eventually Sütterlin could keep up with him, with his other breakaway companions unable to close the gap.
As the new leading trio turned onto the Corkscrew climb with 7.5km left, the peloton behind were rearranging themselves to protect each teams’ general classification riders.
Remi Cavagna (Deceuninck-Quick Step) soon moved off the front of the peloton but found it hard to gain time on the remaining leader Pernsteiner. At 6.4km, stage three winner Peter Sagan (Bora-Hansgrohe) was seen dropping out the back of the peloton.
At the same time, Poels of Team Sky attacked on a left-turning hairpin in the road, bringing with him fellow GC contenders Bennett, Porte and Woods. The latter then overtook Poels but was unable to shake off the other three.
They all crested the top of the climb together and began the descent with an eight second lead over the chasing group. At 2,000m from the finish, though, the leaders were swamped up by the Mitchelton-Scott-led peloton and they all made it into Campbelltown as one group.
Sanchez was at the front of the 20-man pack as they took a turn to the right into the final 500 metres. The Spaniard hesitated in sprinting at first, looking back, but he then went full-gas.
He was unable to power away, though, and Bevin quickly latched onto his back wheel. The race leader then swung to his left and charged beyond Sanchez. But Impey was directly behind and darted further to the left to speed past Bevin and take the win. It was the second successive stage Sanchez had finished on the podium but not the top step.
Tour Down Under 2019, stage four: Unley to Campbelltown (129.2km)
1. Daryl Impey (RSA) Mitchelton-Scott, in 3-03-27
2. Patrick Bevin (NWZ) CCC Team
3. Luis Leon Sanchez (Esp) Astana
4. Ruben Guerreiro (Por) (Katusha-Alpecin)
5. Rubén Fernández (Esp) Movistar
6. George Bennett (NWZ) Jumbo-Visma
7. Diego Ulissi (Ita) UAE-Team Emirates
8. Michael Woods (Can) EF-Education First
9. Chris Hamilton (Aus) Team Sunweb
10. Dylan van Baarle (Ned) Team Sky, all at same time
General classification after stage four
1. Patrick Bevin (NWZ) CCC Team, in 13-23-30
2. Daryl Impey (RSA) Mitchelton-Scott, at 7 secs
3. Luis Leon Sanchez (Esp) Astana, at 19 secs
4. Chris Hamilton (Aus) Team Sunweb
5. Ryan Gibbons (RSA) Dimension-Data
6. Jan Polanc (Slv) UAE-Team Emirates
7. George Bennett (NWZ) Jumbo-Visma
8. Ruben Guerreiro (Por) (Katusha-Alpecin)
9. Diego Ulissi (Ita) UAE-Team Emirates
10. Michael Woods (Can) EF-Education First, all at 21 secs