Ferrari is on the defensive as a terrible United States Grand Prix has rivals suggesting their recent surge was a result of "foul play".
Sebastian Vettel dropped four places on the opening lap as he reported understeer issues before retiring soon after with a suspension failure exiting Turn 9.
As for teammate Charles Leclerc, though a later switch to soft tyres saw him claim the fastest lap, the Monegasque was over 50 seconds behind race winner Valtteri Bottas in an eerie return to their pre-summer break form.
“It was an extremely hard day,” Leclerc accepted after his fourth-place finish.
“I don’t what went wrong, we need to look at the tyres because from the beginning it was just incredibly hard to find the grip with the car.
“I never found it and then we went onto the hard tyres which didn’t feel great either. Then on the softs, it felt quite OK but not the best day for us.
“The first stint was extremely hard and I think this was the main problem of the race. To be completely honest I have no explanation [why],” he concluded.
Somebody not buying the 'lack of grip' argument was Max Verstappen, who would finish third in Austin.
Asked if he was thought the Italian team's struggle was "strange", he replied: "Oh that’s not strange."
Given the chance to elaborate, he added: "Well, why do you think? You can fill it in yourself."
The Red Bull driver was referring to a technical directive issued this week relating to the engine and more specifically the fuel flow sensor, with suspicions Ferrari were able to use a higher than allowed flow rate without it being picked up by the official FIA sensor.
After qualifying, Lewis Hamilton had suggested the top speed of Ferrari had reduced potentially as a result of the directive, and a similar drop was also seen in the race.
“We just had a discussion about the data from the race, and the speed trace looks totally different to the last few races,” Mercedes boss Toto Wolff said via Crash.net.
“Whether it’s down to the technical directive or down to another issue, I honestly don’t know as we can’t look into what Ferrari has done.
“If someone was doing what the technical directive clarified, it would have been foul play,” the Austrian added.
“The way the technical directive was formulated, it was a severe breach of regulation, so there was not even any talk of grey areas."
That drew an angry response from Ferrari boss Mattia Binotto, who offered his own explanation for the team's sudden slump.
“I believe yesterday we have been very close to the pole position, as it has been in the last races. I think that Seb could have scored the pole yesterday, maybe [he was] a bit too much caution in one corner,” he suggested.
“Charles had a clear problem in the morning, losing completely FP3, and had a downgrade on the engine we fitted in the car. Overall I think that looking at his performance in Q3 and what could have been done without the issue in the morning, I’m pretty sure that as well he was potentially in the pole as well, so I don’t see where is the problem.
“If we look at the race today, we may comment later on, but certainly the speed on the straights was not our issue, while we’ve got clear problems on the grip on the car first stint both drivers."
As for the others' scepticism, he added: “Again, it’s the type of comments [that] I feel are completely wrong. It’s not good for the sport and I think everybody should be a bit more cautious. Thanks."
Leclerc also responded directly to Verstappen, declaring: “I think it’s a joke to be completely honest. He has no clue.
“He’s not in the team. So we know exactly what we are doing and I don’t know why he’s speaking, he doesn’t know anything about us.”
Binotto and Red Bull boss Christian Horner were also seen talking in the paddock post-race.
