Mercedes believes Ferrari has made a significant step forward after nearly being defeated by both drivers during the Japanese Grand Prix.
Lewis Hamilton only finished ahead of Carlos Sainz by 0.854s at the finish, after the Ferrari driver chased him down in the final laps.
Charles Leclerc was a further five seconds up the road in fourth, while George Russell was ultimately 7.4 seconds off Sainz on the one-stop.
Ferrari has historically struggled at the high tyre degradation races, but it managed to challenge Mercedes on pace after defeating the Silver Arrows in Singapore.
Trackside Engineering Director, Andrew Shovlin, believes the Scuderia's recent updates along with the high tyre degradation have exacerbated one of the weaknesses of the W14 at Suzuka.
"Part of it is linked to the temperatures. Some of that [tyre] degradation you get is just as the tyres get hotter and hotter over the first eight laps," Shovlin told media, including RacingNews365.
"I think the performance deficit that was there in qualifying, where we have a bit less performance through the faster corners, is the same thing that's costing us in the race.
"Really at this track, it's just about how much grip have you got in the fast corners, a lot of that will be downforce, and we do look like we're a little bit behind in that regard.
"[Ferrari] did bring an updated floor, so maybe they've moved forward. If we look at some of our recent tracks, that advantage we have on degradation is not as evident now in the season as it was in the earlier races."
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Mercedes explain 'no risk' Russell Suzuka strategy
Mercedes feared Sainz might overtake both Russell and Hamilton at the end, which is why it instructed Russell to let Hamilton overtake for fifth.
Even though the one-stop is what ultimately led to Russell falling behind Sainz, the team believed it was enough to cover the gap to eighth place and Fernando Alonso.
"Whilst the odds of of holding back Sainz on the one-stop were relatively low, the reason that we committed to it was by virtue of the fact that there was nothing to lose," said Shovlin.
"There was no risk to George on a one-stop from Alonso behind, so we stayed with it.
“But it was a difficult strategy to pull off and he did well to manage it. But the [tyre] deg was just a bit too high to make it competitive."