Max Verstappen and Renault boss Cyril Abiteboul are locked in a war of words.
In recent weeks, and especially since Red Bull's switch to Honda power for 2019 was announced, Dutchman Verstappen has stepped up his criticism of the Renault engines he uses.
Renault boss Abiteboul hit back at Verstappen at Sochi.
"We have a very demanding user in the person of Max, and not very quiet," he said.
"I think he should focus on the car."
When Verstappen heard about Abiteboul's comments, he responded: "If he would concentrate more on his own team rather than talking about me, we would already be world champion.
"Yes I ask a lot from my equipment," the Red Bull driver, who turns 21 on Sunday, added.
"I am not here to be seventh and deep in his heart he (Abiteboul) knows that," said Verstappen.
