Kimi Raikkonen accepts Mercedes has found key performance gains over the last two races which Ferrari has been unable to respond to in the fight for the 2018 Formula 1 world championship.

The Finnish driver was stranded in fourth place for effectively all of the Russian Grand Prix having seen Mercedes steal a march in qualifying. Raikkonen's race strategy of going longer during his opening stint failed to pay off looking to produce the overcut to climb the order.

COTA #2 - Tremendous Turn 1

Raikkonen felt Mercedes conserved its ultimate race pace to remain ahead of Ferrari without pushing to the maximum but concedes its overall development drive has been stronger than the Italian manufacturer since the start of the flyaway races.

“We went as fast as we could but they were faster,” Raikkonen said. “Did they push as much as they needed today? Probably not, just enough to keep us behind.

“We’re a bit behind in pure speed, but in the race the car feels okay. But we need to go a bit faster everywhere.

“Who knows what they’ve [Mercedes] done. Let’s see in the next race if it’s still the same or not. Hopefully it’s a slightly different story, more like it was a little while ago. I guess they found something.”

Despite Valtteri Bottas being forced to yield to Lewis Hamilton for the victory in Russia, the Finnish Mercedes driver still moved ahead of Raikkonen in the F1 world drivers’ championship by three points thanks to his second place.