Current Red Bull driver Max Verstappen won last weekend in Malaysia, and now Marko thinks that the team will once again be strong in Japan.
"It could help Sebastian if we are ahead of Mercedes once again," Marko told Auto Bild.
Mercedes notably struggled at Sepang, despite the fact that Ferrari's technical problems meant that Vettel's points deficit to Lewis Hamilton blew out to 34 points.
"We will be strong in Suzuka again," Marko added. "And we are still developing our car.
"In qualifying, Mercedes is still stronger with the qualifying mode of their engine. But in the race we were stronger last time."
Vettel trails championship leader Lewis Hamilton by 34 points going into this weekend's Japanese Grand Prix.