Max Verstappen has stepped up his feud with Renault supremo Cyril Abiteboul ahead of Sunday’s Russian Grand Prix in Sochi.

Verstappen has been certainly forthcoming at explaining his dismay at the situation to Dutch TV for having to take on the Spec B engine in Russia. Because of this, Red Bull will incur a grid penalty and he has not been shy at laying the blame firmly at the Renault boss Abiteboul’s door.

"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."

Abiteboul hit back at Verstappen, stating that he should ‘focus on the car’ and explaining to the media that the strategy call was ‘specifically on the request of Red Bull.’ 

“We had a drivability issue in Singapore in FP1, early into the weekend and, to a far less extent, in qualifying," he added.

“I think we have a very demanding user in Max and not very quiet also.”

And ahead of Saturday's qualifying session, the Red Bull star has fired back once more with another jab at Renault's boss.

"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," Verstappen said, per Motorsport.

"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."

As of next season, Red Bull will be using Honda as their new engine supplier. Renault partnered Red Bull for four straight title-winning seasons between 2010 and 2013 but have struggled to replicate anything like that success since the switch to V6 turbo hybrid engines in 2014.

If Red Bull have a poor weekend in Sochi, you can be sure that this row is likely to run on further between now and the end of the season.