Sebastian Vettel is not convinced Ferrari will be able to maintain the advantage it had over Mercedes in Friday practice when it comes to qualifying for the Russian Grand Prix.
In second practice, Vettel was 0.670s quicker than the fastest Mercedes of Valtteri Bottas and 0.709s clear of title rival Lewis Hamilton. Ferrari's long run pace also looked strong, but Vettel is not convinced the Mercedes drivers are as far off as they look.
"I think they will be fine," he said. "It's a circuit that suits them so they will be strong tomorrow."
He also warned that this time last year the practice pace of the Williams cars led to speculation that they would challenge Mercedes, only for Nico Rosberg to qualify a second quicker than the fastest Williams on the Saturday.
"I don't want to make this personal but I think last year people expected Williams to be the fastest after Friday and if I remember right, obviously it turned out Mercedes was the fastest. That's how sometimes it can be misleading [in Friday practice] and I think there are a lot of things we can play with in the car: fuel loads, engines modes.
"So this track especially there are a lot of things that you can show or not show so I think the most important is that we talk about ourselves our balance, and as I said I was able to improve so I'm reasonably happy."