In qualifying 13th, Sainz became the first McLaren driver to fail to reach Q3 in 2020, but both the Spaniard and team-mate Norris believe the drop in position to be more the result of others improving their performances than McLaren dropping the ball.
Tenth place Norris claimed: "I don't think we have fallen off at all. I think the other teams, which just did a very bad job last weekend, have just done a much better job and done the laps they should do.
"I think we were just in a very good position last week. Maybe the wind was helping us, I don't think it is so much down to the tyres. I think we are on the same pace split between the Mercedes and the other top teams.
"We thought we would be in a similar position to what we are now last weekend, but it was Nico's [Hülkenberg] first weekend in, [Lance] Stroll just didn't do a good lap at all. The Renault's didn't do good laps and now they have just put in good laps and they are clearly a long way ahead of us."
Team-mate Sainz believes vastly different track conditions also played a part in the performance shift.
He added: "There is a big change in track conditions compared to last weekend, and it looks like we got the worst of it by going one second slower.
"We qualified on the medium in Q2 which is the same as last weekend's soft and the car still felt pretty well balanced, it still felt we were not far off extracting the maximum pace of the car.
"It just looks like the others have just done a step into this weekend, probably just the track conditions this weekend helping them and the two drivers of each of the two teams like Racing Point, Red Bull and possibly Renault have performed a bit better."
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