Lewis Hamilton is disappointed that Mercedes’ final upgrade package of 2022 did not deliver the expected performance boost.
Although Red Bull and Ferrari were clearly superior in 2022, the reigning constructors’ champions touched down in Austin with a significant package of upgrades.
The Mercedes package included a new floor, key weight savings, and new front and rear wings.
Engineering boss Andrew Shovlin said on Thursday that a new front wing design was to "improve management of vortices around the tyres".
The FIA, however, ruled that the wing’s five prominent mini-winglets were not legal because they contributed to an aerodynamic ’outwash’ which is against the spirit of the 2022 rules.
"It could be interpreted as a provocative answer to the budget cap story," La Gazzetta dello Sport correspondent Paolo Filisetti speculated.
But Shovlin said the full Austin upgrade - the last one for 2022 - was a "mix to improve performance of this year’s car and ensure that our understanding is correct as we move in the right direction" for next year.
Hamilton, who is yet to win a single race in 2022, qualified fifth on Saturday.
"I am certainly not happy," the seven time world champion told Viaplay afterwards.
"Everyone worked so hard to bring these updates and we are not moving forward. P5 is okay, but it’s hard to see the hard work being done and the gap remaining so big."
When asked what would make him happy, the 37-year-old answered: "A win for sure, but I think if we can keep up, that would be great.
"I expect that we will be able to keep up for a while, but on pure pace we can’t seem to get any closer when we upgrade."