The 153.7-kilometre journey to Arenberg sees the Tour return to the cobbles for the first time since 2018, with 11 sectors totalling close to 20 kilometres.
Van der Poel will be among those aiming to overturn Wout van Aert's lead at the top of the general classification, though he admitted his Alpecin-Deceuninck squad will be "really nervous".
"I think now the real racing can start," van der Poel said prior to Stage 4.
"It's been a few quiet days in Denmark, but also the course in the wind didn't really provide the race circumstances to do something.
"But from today we'll be really nervous, I think. I think there are some chances for us as a team."
"It's just a really small Paris-Roubaix," he continued.
"It's not a lot of sections here but, for sure, it's like every time the run up into the section is going to be more nervous than the sections itself.
"I think it's just going to be really nervous. If you already stay out of trouble and don't have a mechanical, I think you can already go far."
Van der Poel had kept his attention on teammate Jasper Philipsen for the fourth stage to Calais, much like stages two and three, though the sprinter was forced to settle for second place after van Aert powered home in yellow.
Sagan, too, was in the mix, finishing fifth, and the TotalEnergies star believes his prior experience on the cobbled course will help him stand out from his rivals.
"Guys like me who do the Classics have more experience and specific skills for the cobbles than the GC riders and the climbers," Sagan told Cyclingnews.
"That should be an advantage for us. I want to do well."
The Slovakian has won 12 stages and seven green jerseys across 11 seasons at the French Grand Tour, having raced on the cobbles back in 2015 and 2018 respectively.
Tony Martin and John Degenkolb took home the victories then, and Sagan believes this year's edition could be his chance to capitalise on the GC battle and each team's subsequent strategies.
"I've done a few," Sagan said of the cobbled stages in Tours past.
"I did one with Alberto, and then when it rained in 2014 with Cannondale.
"Going for the cobbled stage isn't like riding Paris-Roubaix. It's different because you're in the midst of the Tour de France and usually there's a lot of racing still to come.
"There's also the GC battle that changes the strategy of lots of teams and the way almost everyone races. That'll make it a very interesting stage.
"What will happen? We'll see... for sure I still have something to say in my career. That's why I'm in the Tour de France."
The Tour de France heads to the cobbles for Stage 5, the first time in four years that the peloton has had to navigate the infamous pave featured in Paris-Roubaix. Watch from 9:20pm (AEST) on the SBS SKODA Tour Tracker, with the SBS television and SBS On Demand broadcast beginning at 9:30pm (AEST).
