Lance Stroll believes Williams' 2018 challenger is lacking in almost every way after qualifying 20th and last for Sunday's Bahrain Grand Prix.
After a tough race in Australia two weeks ago Williams hoped it would perform better around the Sakhir circuit, a place where it has had at least one car through to Q3 in the hybrid era.
The Canadian was left unimpressed by the new FW41 after his fastest lap in qualifying left him nearly half a second shy of his best Q2 time in 2017 which led to a 12th place start on the grid.
"It has been a really hard weekend," said Stroll. "It was disappointing for the team with both cars out in Q1 and it was not ideal. A lot of things are wrong. The balance isn't there, the grip is not high enough and we need more speed, so we need everything to go quicker.
"Last year in qualifying, my lap was four-tenths better than it was today. In the race, I hope we can go forward, but we don't have the package today to compete where we want to compete"
Team-mate Sergey Sirotkin was less critical of the car's abilities, after taking 18th, but felt his warm-up laps failed to get the car into the right operating window for his qualifying effort.
"I think we could have hoped for a bit more," added the Russian. "The first lap I did was a really good lap. I don’t think we could squeeze out any more from there.
"The second lap with the second set of tyres was strongly affected by a very messy out-lap where I was fighting three or four cars for position. It was really messy preparation, I started the lap just behind a Sauber, and even then I knew the tyres and the brakes were not there.
"I almost managed to beat my previous lap-time, which shows we could potentially go another three or four tenths quicker, but I don’t know if that would have moved us any further ahead. I think, compared to Melbourne, we actually did a better job, in some terms, we maximised the performance of the car. We are moving ahead in one area, but we are missing something."
