The 160.6 kilometre journey kicks off from Salas before the first of four climbs on the day comes 44 kilometres in with the first of two category 1 ascents Puertu de San Llaurienzu (9.9 km at 8.6%) sure to put a strain on the legs early.
Riders will then descend into a false-flat section with little respite before the next of the category 1 climbs on the Altu de La Cobertoria (7.9 km at 8.6%) rounding out the first half of the stage which could see significant time gaps and struggles even before the finale.
Fortunately, the descent following the second climb gives way to a flat section for some recovery and preparation for what's sure to be an excruciating finale, which begins with the category 2 Altu la Sega o del Cordal (12.2km at 3.8%) and runs straight into the new mammoth ascent to the special category finish (14.6 km at 9.8%).
Profile of Stage 18 of the 2021 Vuelta a Espana. Source: ASO
Known as the 'evil sister' of the other gruelling climb in the region, the Alto del Angliru (12.5km at 10.1%), the Altu d’El Gamoniteiru makes its professional cycling debut as a mammoth task for riders, with the gradient never dropping below 10% on the journey to the summit.
SBS commentator Matt Keenan gave his thoughts on what to expect from the penultimate climb and the stage as a whole, with the peloton almost certain to go all out with only one more trip to the mountains to come after.
"Stage 18, the destination is the Gaimoniteiru," he said in his preview. "It's a new climb in the Vuelta a Espana, and it is brutal. Almost 15 kilometres long, with an average gradient of just under 10%.
"The stage is 160 kilometres with almost four and a half thousand metres worth of altitude gain.
"Obviously early, the break is going to try and get away, they had no luck on the previous stage.
Profile of the special category Altu d’El Gamoniteiru in Stage 18 of the 2021 Vuelta a Espana. Source: ASO
While Keenan acknowledged the breakaway could be a factor, he said the real battle to watch would clearly be for the top three overall, with Roglič (Jumbo-Visma) looking to further consolidate his lead and Australian Jack Haig (Bahrain-Victorious) trying to make the jump from fourth to third.
"The race is on for the podium," Keenan declared. "Roglič looks really secure in the red jersey with a 2 minute and 22 second buffer on Enric Mas (Movistar). It's then [Miguel Angel] Lopez (Movistar) followed by Jack Haig.
"Jack Haig is within a handful of seconds away from the podium and Lopez needs to get time on him and knows he needs to attack.
"It's a big day in a battle for a spot on the podium with a new climb and Jack Haig is right in the mix, but he's got Movistar to contend with."
The Vuelta a Espana continues tonight with the queen stage, a 162.6 kilometre course from Salas to a summit finish on the special category Altu d'el Gaimoniteiru. Watch the action live early from 8:35pm AEST on the SBS SKODA Tour Tracker, then from 9:20pm AEST on SBS VICELAND and SBS On Demand.
