Kimi Raikkonen says Ferrari's latest engine upgrade has not provided a big step in performance this weekend at the Russian Grand Prix.

Ferrari spent three of its remaining nine engine tokens on an upgrade to its internal combustion engine ahead of the Russian Grand Prix, but has looked even further adrift of Mercedes on the power-sensitive Sochi Autodrom. Raikkonen said the upgrade had offered an improvement but the impact was not as big as the media had been speculating.

"It's working as we expected," he said. "There are no massive things there, some improvements here and there, with the whole package in the car, so we take it. But it's not like it's making a big, big difference.

"People are very interested in new engines but we put new parts in the car all the time to try to improve everywhere - it's a very normal thing and all the teams do it."

Raikkonen qualified fourth in Sochi but will start from third once teammate Sebastian Vettel is demoted from second to seventh with a gearbox change. Raikkonen made a mistake in the final corner, but said his lap time could have been much worse.

"I ran wide in the last corner on the last lap, but I've been struggling all weekend to put decent lap together. Thankfully it was better in qualifying, but I was still fighting for front-end grip in a few places. Still, it was good enough for third place, but it will all change for tomorrow. Obviously today it was not ideal, it's disappointing but I'll be starting from the clean side of the track, in third place.

"I've been fighting with the set-up of the car the whole weekend, to make the tyres work as we want, as this is a tricky place for that. It could have been a lot worse today, but we'll try to make a good start for the race and go from there."