Nico Rosberg admits that Mercedes' initial struggles amid the upgrades they brought to the French Grand Prix could be "unsettling" for the team.
The Silver Arrows looked to be making continual progress at recent race weekends and, prior to the action getting underway at the Circuit Paul Ricard, Lewis Hamilton expressed his hope that they could make another step forward in France.
However, Hamilton was left searching for answers after a difficult Friday for the squad, while team boss Toto Wolff described the updated W13's initial performance as "underwhelming".
In Saturday's qualifying, Hamilton clinched P4, with teammate George Russell taking P6, but the seven-time World Champion admitted that the car was still losing time at certain areas of the track.
Struggles could be "unsettling" for Mercedes
Rosberg – who clinched the 2016 World Championship with Mercedes before retiring from F1 – thinks that this will prove confusing for the Brackley-based outfit.
"It seems to be a bit of a challenge there for Mercedes," Rosberg told Sky Sports F1.
"Every time they think, 'Okay, now we're really coming back at them, and then we're bringing an upgrade and we're going to be right there with them'.
"Like this weekend, I think they probably thought they would be pretty close. Suddenly again, they're six, seven, eight tenths back, which is very, very far.
"So I think that probably is a bit unsettling, because the upgrades don't seem to be bringing them closer in the way they're hoping."
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Rosberg expects questions to be asked at Mercedes
As a result, Rosberg expects that Mercedes will be asking questions about why the upgrades are not delivering what they want.
"That then brings some question marks [over] whether what they see in the numbers in the wind tunnel really converts onto the actual car in a real situation on a race track," the German added.
"Maybe they're having some correlation issues there. I'm sure there'll be some head-scratching, because the upgrades have not been progressing as much as they would have hoped and as much as they were expecting."
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