The German car manufacturer endured a challenging season-opening Bahrain Grand Prix, with its W13 no match for Ferrari and Red Bull around the Sakhir track.
But as well as struggling to match its rivals in the high-speed corners, the Mercedes was well down in the speed traps too.
And, with Mercedes' customer teams all battling towards the back in the race, it prompted some speculation about Ferrari and Honda having overtaken the German car manufacturer in horsepower terms.
Asked by Motorsport.com about where he thinks the Mercedes engine stacked up, team boss Toto Wolff felt it too early to make a firm judgement because of the wing solution that was being run.
"We need to analyse the drag levels first before we really make a judgement of whether we're lacking power," said Wolff.
"I don't think that there's big differences between the power units but clearly Ferrari made a big step forward.
"Last year they weren't totally competitive and, if you look again at the singular event in Bahrain, it looks like they've outperformed everyone else."
Mercedes is clear that the rear wing it ran in Bahrain will need to be changed for this weekend's Saudi Arabian Grand Prix, which takes place on the high-speed Jeddah circuit.
And running in more equal drag configurations to Ferrari and Red Bull should at least offer a better insight in to engine power.
Reflecting on the maximum downforce solution it ran at Sakhir, Wolff said that Mercedes would come up with a different solution for Jeddah.
"It's easier to shed drag off a car because you simply take a chainsaw and cut the rear wing into bits," he said. "So that's what we will be doing for Jeddah."
The Mercedes tech solutions for Bahrain
By Matt Somerfield and Giorgio Piola
When considering the drag issue, it might be easy to point a finger at the W13's sidepod concept, especially if compared with the Ferrari and Red Bull solutions.
Its rivals' solutions appear to push the wake generated by front tyre outboard differently, whilst the presence of the sidepod bodywork in the central portion of the car will have an impact on the flow received by the rear tyre.
However, Williams is pretty handy in the speed trap compared to Mercedes and also has a small sidepod footprint, albeit not as narrow, so the issue does not appear to be such a simple one.
Sidepod talk aside, Mercedes' focus remained on its floor in Bahrain and resolving its porpoising issues, with the inboard tunnel strakes trimmed in Bahrain, just as they had been on the last day of testing.
The team also experimented with different floor specifications, with a new variant trialled on Hamilton's car during free practice on Friday.
However, it was abandoned again, as the team focused on setting the car up around the more thoroughly understood option.
