A red-hot streak of form makes Tadej Pogacar favourite for Sunday's Liege-Bastogne-Liege cycling classic, but he faces a showdown with local hero, world champion and Vuelta a Espana winner Remco Evenepoel.

Evenepoel is defending champion while Pogacar won in 2021 and this mouth-watering duel in the pollen-thick air of the undulating roads through 258km of the Ardennes forest is the first real head-to-head between the two.

Thousands of amateurs take part in a secondary race while over half a million roadside fans may attend the race known as 'La Doyenne' as it is the oldest of the ultra-long, crushingly difficult one-day races known as cycling's Monuments.

Two-time Tour de France winner Pogacar has smashed the spirit of rivals such as Mathieu van der Poel on his recent triumphs in the Tour of Flanders, the Amstel Gold Race and the Fleche Wallonne.

The 24-year-old Slovenian has outpowered and out-thought his rivals, but on Sunday meets a man with staggering stamina in Evenepoel, who fans will be expecting to make a relentless long-range break.

Evenepoel will line up wearing the world champion's rainbow jersey for the six-and-a-half hour slog.

"This is the best of the one-day races, I'm the defending champion and my objective is simple, to win," Evenepoel, 23, said Friday.

"I have every respect for what Tadej has achieved these recent weeks. My main focus this season is the Giro d'Italia, but Liege will be the test of that."

It is difficult to keep track in the forests of who is where and how far ahead or behind they may be, and Evenepoel has ample knowledge of the local terrain to chose on which hill to execute his plan.

"As a team we have devised a plan and are confident of pulling it off," said Evenepoel, who has Julian Alaphilippe as minder, just as was the case in his triumphant Vuelta campaign.

The race emerges from the Ardennes into the red-brick Italian quarter high above Liege, where a downhill rider such as Briton Tom Pidcock of Ineos could swoop past the Standard Liege football stadium across the River Meuse for an urban 10km finale as the great spring classic culminates.

There are a plethora of other serious contenders with 25 teams taking part.

The 2018 champion Bob Jungels lines up with Bora-Hansgrohe, who have a second contender in Aleksandr Vlasov.

Dutch climber Wout Poels won in unseasonable snow in 2016, and starts in support of Mikel Landa and Matej Mohoric for a strong Bahrain Victorious bid.

Belgians have won 59 of the 108 editions of the race so far, with Eddy Merckx the record holder with five titles between 1969-1975.