Mercedes' Lewis Hamilton expects a tough battle in the Russian Grand Prix after Ferrari secured a front-row lockout in Sochi.
Championship leader Sebastian Vettel claimed pole on Saturday, with team-mate Kimi Raikkonen edging out fellow Finn Valtteri Bottas for second.
Three-time world champion Hamilton was more than half a second off the pace in fourth and acknowledged Mercedes simply could not match their main rivals.
"Today we got more on top of the tyres, but Ferrari was just quicker," the Briton was quoted as saying by BBC Sport.
"Ferrari's pace is quicker than us in the race so it is going to be pretty hard. We will give it everything we've got.
"I definitely wasn't at my optimum. Normally I'm a lot quicker than I was today, so I need to go and work out why and if I can do anything.
"Obviously I can't change the car, so I'll see what I can do or tomorrow."
Bottas, who was less than a tenth of a second behind Vettel in third, hopes a lengthy run to the first corner will work to his advantage on Sunday.
"We were close in the end but not quite enough," he said.
"As always it is tomorrow that really counts. A second-row start here is not so bad. It is a pretty long run into turn one."