Mercedes team principal Toto Wolff is struggling to understand how the Silver Arrows went from pole position in Hungary to the fourth row in Belgium.
The Silver Arrows had been showing real signs of improvement in the lead-up to the summer break, with Sir Lewis Hamilton and George Russell managing eight podiums in the last six races.
Not only was their race pace looking better – Hamilton looked in contention for the win in Silverstone – but their pure performance was also starting to take shape compared to Ferrari and Red Bull.
That was evidenced by Russell’s pole position at the Hungaroring and, had it not been for a DRS issue, Hamilton may have joined his team-mate on the front row.
Following weeks of enhancing their pace, and a new set of regulations introduced in Spa this weekend, there was plenty of optimism for Mercedes, even after their practice slump.
The German side have often struggled to find pace on Friday, before pulling it back during the remainder of the weekend, but qualifying was a nightmare for their British drivers on Saturday.
Both of them needed to exert more effort than they would have liked getting into Q3, before Hamilton ended up seventh, with Russell eighth.
The seven-time champion could scarcely believe his ears when his engineer, Peter Bonnington, told him that he was 1.8 seconds behind pace setter Max Verstappen, as Mercedes’ rollercoaster season hits its latest low point.
There will undoubtedly be more high ebbs for the Brackley-based side during the final nine rounds of the season; a team that has won eight championships in a row will be just fine, but times are tough for the moment.
The Silver Arrows are helped by the fact that Verstappen, Charles Leclerc and Esteban Ocon all have penalties, meaning that Hamilton and Russell will start fourth and fifth, respectively.
This is of little consolation to Wolff though, who could not quite believe what he was seeing having watched Russell take his maiden pole in Budapest.
“It is the worst qualifying session I’ve had in 10 years,” he said.
“Irrespective of what positions we are going to start, being on pole at the last race in Hungary and then three weeks later, being nowhere is not acceptable.
“The car is draggy on a straight line, Lewis said it is like dragging a parachute behind him, there is not one positive I have heard about how the car performs.”
The Austrian took to the Mercedes Twitter account to deliver a similar sentiment to the fans, but expressed his optimism that his drivers can deliver a strong result on Sunday.
“Four weeks ago we were on pole in Hungary. Today, we were 1.8 seconds off pole. And nobody in the team thinks that kind of gap is acceptable,” said Wolff.
“Hopefully tomorrow we will have better race pace than we showed today, but we know we still have a lot of work ahead of us.”
Carlos Sainz will start on pole due to Verstappen’s penalties, with Sergio Perez and Fernando Alonso lining up behind him.