Helmut Marko has played down Red Bull Racing's chances of winning the world championship this year, despite the team's promising potential.
The Milton Keynes-based outfit showed considerable momentum in the latter part of last year, with Max Verstappen winning in Malaysia and in Mexico.
While he expects Red Bull to race at the front once again with rivals Mercedes and Ferrari, taking top honours at the end of the year will prove challenging, according to Marko.
"I don't think we're in a situation where we can already go for the world championship, " the Red Bull motorsport boss told Auto, Motor und Sport.
Marko sees Mercedes and Ferrari's ability to put their full weight behind Lewis Hamilton and Sebastian Vettel as an advantage when fighting for the title, while Red Bull applies a policy of equal chances.
The Austrian recognizes however that a strong driver pairing, in this case Daniel Ricciardo and Max Verstappen, helps to push a team forward as a whole.
"If you have two equally strong drivers, they both go for maximum performance, and they push the technicians and the chassis to peak performance.
"But when you have only one driver that goes to the limit, you do not know where you really are."
However, Marko does see Red Bull immediately challenging for race wins when the season kicks off in Melbourne, thanks to the timely design of its new RB14 and the expected progress of its Renault power unit.
But the Austrian is also wary of his rivals' advancements over the winter.
"The Renault engine should be more reliable and powerful in 2018, and we'll be fighting with a competitive chassis at the outset.
"But Mercedes is producing a new engine, so the question is whether they'll have an even bigger advantage. If the engine does what we're promised, then we should be a lot closer to Mercedes."
Marko is putting a lot of faith in Red Bull's RB14 chassis which received the significant input of design guru Adrian Newey, insisting the team worked ahead of schedule this time to ensure its car hits the ground running when pre-season testing kicks off in Barcelona in just over a week.
"Adrian saw that for the first time that we were able to beat Mercedes on our own and that you can race at the front when the engine is performing well.
"In the past we've always been stronger in the second half of the season. The analysis showed that we always tried to leave it as late as possible, but it doesn't help to try and find a few hundredths every two weeks.
"It's more important that you go into the season well prepared.