Kimi Raikkonen says Ferrari was taken by surprise by its lack of pace in the opening three hours of Singapore Grand Prix practice.
Many tipped Ferrari as favourites coming into the weekend but it was Red Bull who topped both Friday sessions. Though neither managed clean laps, Raikkonen and teammate Sebastian Vettel finished ninth and 11th, while Ferrari and Mercedes appeared to be behind the race pace shown by Red Bull over the higher-fuel runs.
Raikkonen believes the team has a lot of work to do ahead of qualifying on Saturday.
"It wasn't ideal in the afternoon but overall not a lot of things made sense," he said. "First of all we need to make sure we have everything where we want and have a good set-up. Obviously the tyres are always the key. It's not any different here than other places.
"For sure I expected a bit more but obviously it wasn't. Tomorrow was another day."
Ferrari's strongest showings this year have been at Monaco and Hungary, two high-downforce circuits similar to Singapore, on weekends it was immediately able to extract its best performance.
When asked why the team had a slow start compared to Monaco, Raikkonen said: "Obviously it is two completely different circuits. It is not exactly where we expected to start and [we need to] work forward. It's not the first time and it's only Friday."