Williams had a peculiar Friday at the United States Grand Prix as it ended practice with its fastest Formula 1 car slower than Cadillac and the other 8.1 seconds off the pace.
Alex Albon was an exaggerated slowest in FP2 (just as he was in FP1) but the team's real pace was still disappointing, with Carlos Sainz even behind Valtteri Bottas's Cadillac.
A track-limits deletion was behind Albon's particularly unusual deficit and the strangest Friday of 2026 was partly down to Williams sacrificing typical in-weekend work for 2027 development help in FP1.
This meant aero testing on hards in FP1 followed by a short medium-tyre run, as Williams chief trackside engineer Paul Williams said the team had "balanced off performance for this weekend versus long-term learning" because "this track's very good for aero data collection".
Sainz said: "We decided to invest FP1 on a track that we knew we were going to be weak [on] to understand how to basically map the car in order to learn from this year's car as much as possible for next year's car.
"We know we have a lot of weaknesses on this year's car on a track like this and we want to make sure we understand it and we map it to try and get it right next year in the windtunnel."
Then the focus in FP2 was a more standard Friday plan just with a heavier emphasis on high-fuel running as Williams knows its one-lap pace is likely to be lacking anyway - although its long-run pace looked weak in the midfield too.
The Circuit of the Americas is a punishing track as its layout comprises a mix of medium- and high-speed sweeps, long-duration corners, and bumpy heavy braking zones.
This exposes a lot of Williams's underlying weaknesses of recent years and the specific shortcomings of its 2026 car.
In FP2, shortly after Sainz complained the car was a mess and he had no confidence in the rear, Albon reported zero confidence under braking.
"When you have no downforce you're going to suffer either on braking or on high speed," said Sainz.
"We know this year we lack a lot of downforce in the car and especially when it gets bumpy, when it gets high speed, when it gets hot, when it gets windy - like it gets in COTA - the only thing that saves you is downforce and that's what we don't have on this year's car.
"So we're working on it, we are braced for a tough weekend, don't expect any miracles, but at least we are investing in learning as much as possible for next year."