Peter Sagan (Bora-Hansgrohe) assumed control of the Tour Down Under when he won the feared Norton Summit stage, winning the select group sprint from South African Daryl Impey (Mitchelton-Scott) and Luis Leon Sanchez (Astana). Sagan also assumed control of the overall race lead.
While a 128km stage isn't really testing in terms of distance, the 43 degree average temperature between Norwood and Uraidla made today's fourth stage of the Tour Down Under one of the most arduous.
Two riders from the UniSA team braved the heat and went on the attack, establishing a lead of nine minutes. The gap to the breakaway meant the peloton could not rest, making for an all-round difficult stage heading toward Norton Summit.
The peloton got the better of the break in the end, reeling them in just before the category one climb began with 13km to go. The main group flew into the base of the climb and riders were instantly getting dropped. It wasn't long until only 35 riders remained in the lead group.
Team Dimension Data for Qhubeka were well poised for the finale, with three riders positioned in the group of favourites. Team leader, Tom-Jelte Slagter had the support of Ben O'Connor and Scott Davies going over the top of Norton Summit. Richie Porte was first to crest the climb, closing the gap to Nicholas Dlamini's King of the Mountain's jersey to 16 points.
As the 35-rider lead group made their way over the rollers that populated the final 7km, a few attacks went off the front, but with 1km to go it all came back together. Sagan was the fastest from the group despite a strong challenge from Impey.