Robert Kubica says he is only 20 per cent ready for his return to F1 in 2019.
Having failed to get its new car ready on time for Barcelona testing, the Williams team's rookie driver George Russell admitted: "I would be lying if I said that we are not the slowest team right now."
Not just that, the end of the British team's Barcelona programme was also affected by a lack of spare parts.
"If you already have problems finishing the car then you also have problems with the spare parts," Kubica said.
"In the end we got the maximum we could from it, but the maximum is not enough.
"I know maybe 20 per cent of what I should know. Everything else is unclear," he added.
And so Kubica said Australia, his first grand prix since 2010, will be little more than an "extended test".
"It's going to be difficult to do my first race eight years after my last race without any reasonable testing, but I can only try to prepare myself as best I can," he said.
"We are going to Australia blind, but that is the reality. I cannot change the situation."
