Mercedes has called a meeting at its Brackley factory on Monday with both of its drivers to help ascertain where it has gone wrong with its Formula 1 car.
The team started the season alongside Red Bull as one of McLaren's main rivals, with George Russell taking four podiums in the first six races.
But more recently, despite a 1-3 result in Canada at a circuit that perfectly suited the characteristics of the W16, its form has fallen away.
A largely lacklustre performance at last weekend's Belgian Grand Prix, where Russell came home a lonely fifth, comfortably behind Charles Leclerc's Ferrari and Max Verstappen's Red Bull.
Russell said the result fell far below expectations.
"It was very underwhelming in terms of the performance," he explained. "We need to really understand what is going on and why we've taken such a step backwards.
"These conditions [in Belgium], you would argue, are ideal for us and our car. And once again, it's been the worst performance of the season.
"So we're going to have a big sit down this week and try to figure it out."
Rear instability problem
Its core issue seems to be that both drivers are struggling with rear instability on corner entry. The team suspects that its woes have been triggered by recent developments putting its car in a less happy place.
Mercedes trackside engineering director Andrew Shovlin said the mission now was to find out where along the way it has taken a wrong step with its car.
"We had early on in the year a car that was working well at pretty much every circuit," he said. "We were generally fighting for the second row of the grid, if not the front row.
"It is quite likely something that we've changed on the car, and we just need to recover a bit. [We need to] get back to a baseline where it's working more normally."
Flexi wing impact?
Russell suspected that this may be linked to changes that Mercedes had to make from the Spanish GP in response to the FIA's clampdown on flexible front wings.
"We went in a slightly different direction afterwards to sort of tackle the issue of the change of front wing, and clearly since that point we've taken a big step backwards," said Russell.
"It could be as simple as just reverting to something that we had earlier in the season.
"Of course you can't do that with the front wing but in terms of the rest of the set-up, I don't know. It seems quite strange how we've gone so far backwards."
Shovlin reckoned the situation was more complicated than just being related to a stiffer front wing.
"It's probably true for anyone that the TD [flexi wing technical directive] won't improve stability," he said. "But we did have this wing on the car in Montreal, and it was fine.
"The fact is, other people are able to balance their cars a bit better. There's no doubt a solution in there for us.
"But as I said, we're just looking at all the steps that we've taken with the car design over the last number of races. It isn't just the front wing that's changed, and I'm sure there's more that we can learn."
Shovlin said that getting together with the drivers was important to help the team get a proper handle on what particular aspect of its car may have sent it down the wrong path.
And Mercedes is looking at seeing what changes it can make immediately, which could allow it to plot a recovery in time for this weekend's Hungarian GP.
"It's definitely possible for us to look at changing aspects of the car for Budapest," he said. "How deep we go will depend on what parts we've got around us.
"There's quite a lot that we've changed. So we've got a meeting with the drivers [on Monday] to go through some of what we've done over the year to try and make sure that our efforts are focused on the right things, not just changing things for the sake of it."
Antonelli being punished
Shovlin said he believes that Antonelli's recent struggles, which included a particularly difficult Belgian GP weekend where he failed to score any points again, are linked to the Mercedes car being more difficult to drive.
He said Russell has an advantage in extracting more from the car because he has been "leaning on his many years of experience in an F1 car to try and make the most of a difficult car when it comes to qualifying".
"Kimi hasn't got that to drop back on," added Shovlin. "That's probably why you've seen a bit of a shift in his results recently.
"But again, it goes back to the fact we've got to solve that problem, because there's still a long way to go this year."
