The Brackley-based team had hoped to take the fight to Red Bull at Spa, but Lewis Hamilton struggled to find a good set-up with the car throughout the weekend and finished third.
With Monza also demanding the kind of low-drag performance that was required for Spa, Mercedes has been working hard on implementing solutions that it hopes will deliver a step forward in form for Italy.
Mercedes motorsport boss Toto Wolff said: "In Monza, we will use a refined version of the low-drag package introduced at Spa. We hope to see an improvement in race pace after the lessons we learned over the race weekend in Belgium."
Team principal Ross Brawn revealed after Belgium that the outfit had been slightly baffled as to why its pace was lacking.
"I don't think we quite got the car right," he said. "We were there or thereabouts but it didn't feel quite as sharp as we have had the last few races: whether that was because of the set-up philosophy, or some of the changes we made, we will have to go back through.
"The aero package certainly did what it should do, but we were not very good in sector one, and our performance through Eau Rouge was poor.
"Our car had good grip in the [other] fast corners though, which was slightly odd."