This weekend's inaugural grand prix in Azerbaijan takes place on the second longest track on the calendar with a straight that measures 1.4 miles.
Renault has made strides with its power unit this year, with its latest upgrade generating a lap time gain of around 0.5s per lap.
That in turn has improved Red Bull's fortunes, with the team winning in Spain, challenging for victory in Monaco and showing increased competitiveness on a power-sensitive track in Canada.
But Marko was pessimistic ahead of the European Grand Prix saying: "The extremely long straight will not benefit us.
"Our computer simulations showed we will lose 1.2s per lap there.
"This is almost impossible to make up in the corners, though we have an outstanding car."
Despite this view, Marko is hopeful Red Bull will "be chasing Mercedes and on the same level with Ferrari" on the 3.732-mile street track.
Reflecting on the Canadian Grand Prix, Marko bemoaned how both Daniel Ricciardo and Max Verstappen were hurt by the cooler conditions, "which hindered our tyres to reach the optimum operation window".
Marko said Ricciardo's race was "destroyed" by the virtual safety car phase, when he claims he was on the verge of passing Verstappen.
Red Bull issued a team order early in the race when it appeared Ricciardo was quicker than team-mate Verstappen, who was instructed at one point not to hold up the Australian.
No change of position occurred, which team boss Christian Horner insisted after the race was "fine" as Verstappen began pulling away from Ricciardo after the virtual safety car.
Marko echoed Horner's view and praised the performance of Verstappen, who finished fourth with Ricciardo fading to seventh.
"His defence against Rosberg was certainly the highlight of the race," he said. "He could not have done any better."