Max Verstappen claims Renault would "already be world champions" if Formula 1 boss Cyril Abiteboul was not "moaning about me all the time".
The Red Bull driver's comments, made on Dutch television, continue a war of words with the Renault chief in the build-up to Sunday's Russian Grand Prix.
That started when Verstappen claimed Renault's upgraded Spec C engine would not perform as well at high-altitude later in the year, requiring Red Bull to take another Spec B and grid penalties in Russia.
Abiteboul hit back by saying Verstappen should focus on his car and reminding the Dutchman that Red Bull pushed for this engine plan.
Verstappen has now told Ziggo Sport: "If he would concentrate a little bit more on his own team instead of moaning about me all the time, they would already be world champions.
"I don't understand these things. He just has to concentrate on himself. I always concentrate on myself when I'm in the car.
"I don't think that's the issue, but we'll see."
Abiteboul was irked by the suggestion Verstappen had said Renault's new engine would not perform as well in the upcoming races in Mexico and Brazil and clarified that the step from the Spec C would be the same but there would be a driveability concern.
Verstappen said he was referring to reliability rather than stating the Renault would have less power.
"That man is just frustrated," said Verstappen. "I'm just very honest. I just explained clearly why we have to revert back to the B [spec].
"That turbo won't last in Mexico and Brazil. If we would race with that [engine] then we would not make it to the finish for sure.
"So, it's not that I'm lying. I just think that he can't take it very well, that I am too realistic and too straightforward.
"I demand a lot from the equipment, but I'm here to win. I'm not here to become seventh like they are doing."
Renault decided not to comment when approached by Motorsport.com.
Red Bull is leaving Renault at the end of the season to switch to Honda engines, bringing a title-winning but acrimonious partnership to an end.
Verstappen has become more and more outspoken against Renault since that news was confirmed, highlighted by complaints over his team radio in Hungary and Singapore as well as direct comments to media.
Renault's revived works team is in its third season and fighting for fourth in the world championship, with ambitions of joining the Mercedes/Ferrari/Red Bull fight in 2021.
As an engine supplier it helped Red Bull to four straight drivers' and team's titles from 2010 to 2013, but has been overpowered by Mercedes and Ferrari in the V6 turbo-hybrid era that began in 2014.
Additional reporting by Erwin Jaeggi
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- Formula 1