McLaren says it was willing the "pay the price" in a wet qualifying session by banking on a set-up optimised for a dry race.
Off the back of its 1-2 win in Hungary, McLaren looked strong again in dry Friday practice at Spa-Francorchamps, but in a wet qualifying session on intermediate tyres Norris and Piastri struggled much more with their MCL38.
As Norris and Piastri settled for fifth and sixth in Q3, team boss Andrea Stella said McLaren made sure not to compromise its race day performance by adding too much downforce for Saturday's wet conditions, hoping his drivers can cash in on that decision in what is expected to be a dry grand prix.
"We didn't want to compromise our set-up for today's conditions, because we know that tomorrow we need the top speed," Stella told Sky Sports F1. "We were ready to pay a bit of a price in qualifying because we want to have the most reasonable car tomorrow in the right conditions.
"At the moment, every weather forecast model is predicting dry, so we wanted to make sure that we didn't have a glorious Saturday and then the car is not in condition to capitalise on Sunday."
With Saturday's fastest driver Max Verstappen demoted to 11th due to an engine penalty, which moves both Norris and Piastri up one position, Stella felt both his drivers still had a good chance to win the race on Sunday.
"It's actually the easiest circuit for overtaking and it's a race that will be dominated by the tyre behavior, so I think the starting position is not the dominant factor," he added.
"It's important that we are there at the end of the race, we do a good job managing tyres and we use the potential of the car in terms of top speed. If we blend all these factors together, we can have a good Sunday."
But Norris cautioned that Red Bull looked quicker in the dry too, which makes overtaking second-placed starter Sergio Perez not so straightforward and could allow Verstappen to come through the field as well.
"The whole weekend Red Bull has been a step above us, even though we were a little bit quicker yesterday," Norris warned. "I just don't think Red Bull showed their cards at all and we did.
"From my side I was always one step behind and just always a little bit on the back foot, so to kind of still aome way with a P5 I was actually surprised and happy with.
"We still have to overtake some quick cars tomorrow, like the Red Bull of Perez. The slightly lower downforce that we have potentially hurt just a little bit today and hopefully pays us back tomorrow."
