Lewis Hamilton believes Mercedes still has time to rescue its Belgian Grand Prix, and is not ruling out fighting for pole position on Saturday.
The Briton admitted the team had taken a backward step relative to its form in Hungary, but said he is still confident it can make the changes needed to return to the front.
"It has not been a particularly tough day, just not a good day," Hamilton said, after ending up only 12th and 15th in the two practice sessions.
"I'm struggling - the car doesn't feel as good as it did in the last race - but I'm still hopeful.
"I don't think the car is bad, I just think we need to refine the set-up. The Red Bulls are obviously very quick, but I don't think they're unbeatable.
"I don't feel we started on the right foot. We have some things to change this evening, but we still have time."
Asked if he believed he could fight for pole, Hamilton added: "At the moment I don't, the car is really not on the pace, but hopefully this evening we'll change it.
"At the moment we're a long way off, but we'll find it tonight."
Hamilton said the weather had played a part in Mercedes' poor start to the weekend, and denied the team was deliberately sandbagging.
"It was obviously two different sessions, and the weather this morning hampered everyone a bit," he said.
"It's not the case [we're hiding], we're just usually lost and we find our way on Saturday.
"I know why that is. [It is] not every time we'll be able to find the right way, but I hope this evening we can make the right changes which will help.
"The important thing is we got some long runs done - that's the most important thing for the race."