Valtteri Bottas has conceded Mercedes are "really struggling" in Singapore and have a mountain to climb if they are to get on at least one car in a podium spot.
The Finn in particular has found life very tough at the Marina Bay street circuit, qualifying in P6 and a whopping 1.3 seconds behind pole-sitter Sebastian Vettel.
"Definitely, the gaps are too big for us," said Bottas.
"From two weeks ago at Monza it was pretty good for us, and now we're really struggling.
"It just highlights that we still have issues producing enough downforce and mechanical grip at a track like this, so that is an area we really need to work on.
"We tried a lot of different set-ups this weekend and in practice three, making big changes, bigger than we normally do, because we were just way off the pace."
On Mercedes' chances in the race, he added: "Tomorrow is the race and we know the car is not quick enough for the podium – that's a fact.
"We need to get all the other areas right and maybe it's possible."