Daniel Ricciardo admits the big gap to Mercedes is "unexpected" and concedes it could take a "little while" to get closer.
The former Champions struggled throughout pre-season and things didn't improve much at Albert Park this weekend as Ricciardo qualified seventh fastest with Russian Daniil Kvyat 13th.
Kvyat's Red Bull debut was over before it even started as his RB11 suffered a gearbox problem on his way to the grid.
Ricciardo got away cleanly and managed to pick up a decent haul of eight points after finishing sixth.
The Australian, though, was more than a lap down on race winner Lewis Hamilton in the Mercedes.
"Winter was a lot better than last year but in terms of pace we're not one second off, it's more 2s, 2.5s off," he is quoted as saying by Autosport.
"We know where a lot of that lies but obviously there's some more as well and that's unexpected.
"We're definitely behind, but it is what it is and we've got to try to make the best of it. I'm sure we will get there but it could be a little while."
The 25-year-old found himself stuck behind the Sauber of Felipe Nasr throughout the race. He initially looked like he would overtake the Brazilian during the early stages, but fell off the back of the Ferrari-powered car as the race continued.
"I was trying. The whole race was trying to make something happen, but we could not get close to Sauber," Ricciardo said.
"I tried to do a few things, but that was all we could do. The initial launch felt all right, but then we got a few issues with driveability and that hurt me coming up through the gears.
"Hopefully the next few [races] can turn around.
"We will just try and analyse it all. Not over-analyse it, we know where we stand, what we are going to do, so just get the basics right and try and find something.
"If there is an obvious thing that is missing, I don't think there is, but if there is something else, [we will] just try and get on top of it sooner rather than later."