Scotland’s Oscar Onley won the fifth stage of the Tour Down Under but missed out on the overall lead on countback.

The 21-year-old dsm-firmenich PostNL rider triumphed on a sprint up Willunga Hill on Saturday for his first professional victory.

Welsh rider Stephen Williams, from Israel-Premier Tech, finished second and claimed the leader’s ochre jersey.

Sunday’s final stage will see the riders travel 128.2km (79.7 miles) from Unley to Mount Lofty.

Both Onley and Williams were credited with the same overall time of 16 hours, eight minutes and 18 seconds after a tough day which ended with Onley taking charge around the final bend to hold off his fast finishing rival.

Ineos Grenadiers’ Ecuadorian rider Jhonatan Narvaez was third while France’s double world champion Julian Alaphilippe (Soudal Quick-Step) had looked in a strong position before being overtaken by the leading trio inside the final 300m.

The overnight leader, Mexico’s Isaac del Toro Romero (UAE Team Emirates), dropped back to fourth in the general classification, five seconds off the lead.

“It’s pretty incredible, I knew I was in good form coming here and I really wanted to do something on these final climbing stages, but against these guys I wasn’t really sure,” said Onley.

“It’s quite an iconic climb and to put my name on there is very special.

“I am going to have a lot of work to do tomorrow, but I have some really good team-mates with me and I’m sure they will help me out.”

Williams was thrilled to have snatched the overall lead with his second-place finish.

“It will be a tough stage tomorrow,” he said. “It will be hard to control, everybody’s still very close on [general classification], the top five or six guys all within a handful of seconds.

“I expect a pretty stressful day, but the guys I have here are so experienced and class that I have no worries that we will do our best to fight for it.”