While admitting that Red Bull was pleased with the engine side of proceedings at the season-opening Australian Grand Prix, Dr Helmut Marko believes the team was lacking with its chassis.
Melbourne saw Red Bull and Honda kick-start their relationship, with Honda powering Red Bull to a third-place finish.
Marko described the weekend as "ideal" when referring to the engine performance, but says that the car itself was not running optimally.
"We had an ideal weekend in Melbourne in terms of engines," said Marko. "The engine ran smoothly from day one until the race. Also the adaptation, drivability and all that.
"In terms of the chassis, we still had deficits. Certainly to a degree because of the fact that we never drove with the full package in Barcelona because [Pierre] Gasly destroyed essential parts that we only had one of.
"We let ourselves be irritated and we went much too far in the hard direction with the set-up.
"You could see that in the third practice with [Max] Verstappen. From curve 3 to 4, the wheels went crazy, he drew black lines there. It was like a rallycross car.
"And we're also far from at the optimum of what the chassis can do. But that's nothing that can't be repaired in a very short timeframe."
Marko says that it's too difficult to guess the pecking order until after the following Grand Prix weekends.
"Maybe Mercedes doesn't even know why they were so far ahead in Melbourne," he said. "Let's call it 'Melbourne effect'. The track temperature was between 40 and 44 degrees. That's 15 degrees more than in Barcelona.
"I think we'll only see the exact balance of power on the upcoming circuits, which have more significance, like Bahrain and China."