SOCHI, Russia (AFP) - Charles Leclerc and Sebastian Vettel hope Ferrari's overnight homework on their cars can deliver the extra speed they need to claim another pole position in Saturday's (Sept 28) qualifying for the Russian Grand Prix.

The Monegasque and his German team-mate were second and fifth in Friday's second free practice as Red Bull's Max Verstappen set the pace, both Ferrari men ending the day believing they had more to offer.

"I think there is quite a lot of lap time to be gained on our side," said Leclerc, who is seeking a fourth successive pole position and third win in four outings.

"It's really all about finding the right balance."

As Dutchman Verstappen is set to take a five-place grid penalty, Leclerc and Vettel know that they could fill the front row even if the Red Bull man stays on top.

"It's a bit strange," said four-time world champion Vettel, who ended a 13-month stretch without a win at last Sunday's Singapore Grand Prix.

"We tried some stuff today and now we need to decide what to keep and what to get rid of."