Mercedes' trackside engineering director Andrew Shovlin admitted that there was a bigger gap than expected between his drivers and Red Bull's Max Verstappen.
The Dutch driver was almost four tenths quicker than Lewis Hamilton in the final round of qualifying, having been more than seven tenths quicker than anyone in the earlier Saturday afternoon practice
"It's disappointing at the first race to be looking at a 0.4s gap to pole," acknowledged Shovlin. "But at least we know the performance we need to find going forward.
"It's also no secret that we've been struggling with the car around this circuit," he added. "It's nowhere near as easy to work with as the W11.
"But everyone in Brackley and Brixworth has been working hard since the test and we've learnt a lot about the W12 and found a more predicable balance, even if we're lacking overall pace."
Team principal Toto Wolff admitted it was hard to accept that Mercedes had slipped so far away from their main rivals over the winter.
"It's hard to swallow, although we knew Red Bull would be strong," he said. "We're losing on the high speed [corners]. We can clearly see there's a deficit.
“We're losing a little bit on the engine side in terms of derate. We are not yet in a happy place with our energy recovery, but it's not one thing we point to where we can say this is the big gap.
As the fair sportsman that he is, Wolff was quick to praise Honda for the performance gains achieved by its new power unit.
"Honda has done a great job," he said. "You just have to say when they've done a really good job, full stop.
"They delivered the power unit which is extremely competitive - look at where AlphaTauri is. We just have to take it as sportsmen
"They left no stone unturned, and no resource un-utilised to finish the job properly. It's good motivation for us, and I'm happy for them."
Even so, Mercedes can take solace in knowing that it had succeeded in putting both Hamilton and Bottas through ot the final round of qualifying on Saturday despite sticking to the slower medium tyres, unlike others such as Ferrari and McLaren.
"We'd wanted to get both cars onto the medium tyre to start the race which we managed to quite safely," confirmed Shovlin. "It was good effort by the team and drivers, and should put us in a strong position for [the race].
"It's hard to read where we are on race pace from the Friday long runs as we didn't land the car in the right window but we're fairly confident we've improved the rear grip so it will be less of a handful in the race.
"We might not be on pole but we have two cars at the front and an extra set of the hard tyres, so hopefully we can create some opportunities from that.
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