Max Verstappen disagrees with Sergio Perez's claims that Renault's engine is now on a par with Mercedes' power unit.
Verstappen captured Red Bull Racing's only podium to date this season when he finished third in China, but isn't sure his team's engine a partner has caught up with its German counterpart.
"Of course they (Renault) are working really hard," he said.
"We're also working really hard to improve the car. But I think there is still quite a deficit. So we need to continue working hard together to make it better in the upcoming races."
The young Dutchman said Mercedes still held an advantage, mainly in qualifying.
"Mercedes has a mode where they can turn it up," he said.
"In the race they cannot use it as much because you can't run the engine like that the whole race. That's why it looks better in the race but from our side, it's more or less the same.
"We don't have this massive power mode [for qualifying]."
GALLERY: All the pictures from Thursday in Sochi
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