Christian Horner reckons the only thing that is certain from pre-season testing is that Mercedes "have retained their advantage" over the chasing pack.
Although it was Ferrari who claimed the majority of the P1s in testing, five of the eight, and finished the eight days with the 1-2, it was Mercedes who impressed the most.
The reigning World Champions clvered 1329 laps compared to second placed Toro Rosso's 1091. Red Bull managed 814.
Added to that neither Nico Rosberg, who was third fastest overall, nor Lewis Hamilton tried the ultra-soft Pirellis, prefering to do most of their running on the medium compounds.
"I think one thing's clear from pre-season… you don't need to be Einstein to work out that Mercedes have retained their advantage," said Red Bull team boss Horner.
"They have reliability and pace. In terms of pace they never really showed their hand but the reliability was incredibly impressive.
"Ferrari look like they have made a bit of a step, but thereafter it's anybody's guess.
"Toro Rosso, with their new engine, have made a good step and of course Williams will be in good shape. Force India also finished last season well also, so let's see."
Pressed as to whether he believes Red Bull 'might fit into that picture', the Brit said: "Absolutely no idea until we get through the first three races, because obviously Melbourne is a bit of a one-off circuit.
"Let's get through three races and then I think there will be a clear order."
Daniel Ricciardo was ninth in pre-season testing while Daniil Kvyat was 13th of the 23 runners.