The Austrian Grand Prix, Red Bull's home race, was the scene of its first victory powered by Honda engines in 2019, courtesy of Max Verstappen.
While in 2020 Mercedes proved superior in Spielberg's two races, last year Verstappen won both the Styrian and Austrian Grand Prix at the venue from pole position.
When asked why Verstappen and Red Bull are so strong in Austria, Red Bull advisor Marko revealed Honda's "special turbocharger" works especially well at altitude, with Spielberg's hilly Red Bull Ring sitting at over 600 metres above mean sea level.
"It's the engine," Marko told Red Bull-owned Servus TV. "And Honda has a special turbocharger, which has a small but decisive advantage in the altitude, which is 670 meters there, in about the past few years.
"And that has also been very important for us. There we celebrated our first victory with the Honda engine.
"That was quite crucial for the cooperation and especially until 2025, that we can fall back on this [power unit] source."
Last week's British Grand Prix at Silverstone saw Mercedes back in the mix with Red Bull and Ferrari, with Lewis Hamilton finishing third after a scintillating late race battle with Red Bull's Sergio Perez and Ferrari driver Charles Leclerc.
But Marko believes its bitter rival will struggle more in Styria due to the bumpier nature of the track.
"I assume that it will be much more difficult for Mercedes again," Marko added. "They have to raise the car. No problem, they are just slower.
"The difficult thing is that you have very fast corners, very tight corners, you have to brake twice from well over 300kph, and finding the right set-up between mechanical and aerodynamic grip is the crucial thing.
"But as I said, Max is the record four-time winner here and is also specially motivated. And especially with this Dutch fan base in the background...it's electrifying."
