Sebastian Vettel expects Mercedes to return to the top of the time table as the Singapore Grand Prix weekend develops.
Mercedes had a quite opening night at the Marina Bay Street Circuit, with Lewis Hamilton fourth fastest, and Nico Rosberg seventh.
"I think it was a good day for us," said Vettel, who finished fifth.
"The car seems to work, but other than that I think we can still improve. I was not entirely happy with my short runs, so for qualifying we still have to improve a bit, but for the race it looked OK.
"Obviously, we can expect the Mercedes to be quick tomorrow: I don't know what happened to them today, they looked a bit slow, but for sure they will change it for tomorrow.
"We know that the Mercedes don't show everything on Friday, and as expected the Red Bulls are fairly quick here as well, so tomorrow it will be tight – I look forward to Saturday."
Räikkönen also agreed with his team-mate's opinion that there is more to come from Mercedes.
"There is always something we can improve but overall the car was behaving well," he said.
"As usual, Mercedes will be very strong and also Red Bull seems to be quite quick here, but today it's only
Friday and it's hard to judge from the lap times.
"Hopefully tomorrow we'll have a good day and then we'll go from there."