Laurent Mekies has pushed back against Toto Wolff amid a growing political row over Formula 1’s new engine balancing system.
The FIA is preparing to assess performance gaps between manufacturers under so-called ADUO rules - Additional Design and Upgrade Opportunities - which could allow struggling suppliers extra development freedom.
Wolff has suggested only Honda should qualify, arguing the rest of the field is already close.
But Mekies disagrees, insisting Mercedes remains clearly ahead.
"The game around the setting of that ranking we’ve been hearing since Bahrain, and we’re not trying to go along with that," he said.
"We recognise that it is a difficult task. We simply tell you what we see."
"What we see is that Mercedes is definitely a long way ahead for most of us. And yes, one party, Honda, is particularly behind."
Mekies even put a number on the gap.
"Three tenths, that’s how we estimate it internally," he said.
The Frenchman made clear Red Bull does not accept suggestions it is exaggerating a deficit to gain extra development freedom.
"We’re not trying to go along with that," he repeated, while hinting Mercedes may have its own reasons to downplay or even hide its advantage.
"Mercedes now has such a considerable lead that they may be tempted - that is understandable."
At the same time, Mekies acknowledged the FIA faces a near-impossible task in judging the field.
"The objective difficulty to judge who stands where, also for the FIA, is big. Very big," he said.
"The objective complexity of getting it right is large, by reasons like the combustion engine opposite the battery and fundamental choices - a small turbo, a large turbo, exhaust gas blowing or not."
"It’s not a fun task to do that."
While Red Bull trails, Mekies insists progress is coming.
"It has clearly exceeded expectations," he said of the new power unit.
"We have to take back those tenths. It doesn’t happen in Miami, but it’s going to happen."
However, he played down the idea that any ADUO allowance would lead to an immediate upgrade.
"Even though you theoretically have the right to do it immediately after the judgment, are we ready for that? Probably not," Mekies said.
"Realistically, I don’t think that you will see it in the first part of the season, at least not at us."