Fernando Alonso believes that the circuit layout at Spa Francorchamps and Monza will mask the progress made by McLaren.
McLaren has endured a troublesome start to its reunion with Honda in 2015, amassing 17 points across the first 10 races, 12 of them coming at the most recent race in Hungary.
While sure that McLaren has made progress, Alonso reckons that the characteristics of the next two circuits will not play to the strengths of the Honda-powered MP4-30.
"The next few races will be important for us: we need to continue our forward momentum, and, with the addition of some tweaks to the car and power unit, we will be looking for more progress and good correlation between the simulator and our on-track performance," said Alonso.
"That might not necessarily appear above the surface in either Spa or Monza, but we'll keep pushing development forward at each race."
Team-mate Jenson Button echoed Alonso's prognosis.
"We can't pretend that we're expecting a huge jump forward in performance - especially at this circuit, as it doesn't suit our car's characteristics - but, after the break, I'm feeling refreshed, positive, and ready to continue the solid progress we've made so far," said the victor of the 2012 race