Although the German car manufacturer is coming off the back of a win in Russia, it knows its success there was down to good timing with a virtual safety car pitstop.
With Ferrari having been quickest at all the races since the summer break, Mercedes knows it is currently on the backfoot.
Speaking before travelling to Japan, Mercedes motorsport boss Toto Wolff said he hoped the developments would make a difference, but he was not expecting a dramatic transformation in pace.
“The win in Sochi doesn’t change the fact that Ferrari had a stronger start to the second part of the season than we did,” said Wolff.
“We’ll bring some minor upgrades to the car in Japan which will hopefully help us take a step in the right direction.
“However, we know that we need to extract absolutely everything from our car and the tyres if we want to be able to challenge for a win.”
Wolff said after the Russian Grand Prix that the team’s switch of focus to 2020 led to the development of this year’s car to slow down, a factor that has contributed to Ferrari becoming the team to beat.
The Italian squad, meanwhile, believed that its form has been boosted by bringing forward development work planned for next year.
Despite its performances after the summer break, Ferrari trails Mercedes by 162 points with five races remaining and 220 points to win.