Max Verstappen admits Red Bull has taken a step backwards in its outside bid for the 2018 title.
And he says the main reason is not the car, but the Renault engine.
Red Bull's chances 'dwindling'
"The difference is now greater than it was at the beginning of the season. In Canada we were only 0.15 behind them, but at Silverstone it was much bigger. 1.1 seconds," said the Dutchman.
Verstappen said Red Bull's claim about having the best chassis in Formula 1 is still correct.
"We can continue to develop it, but the others don't stand still either. I wish we had more power. But it's just like that.
Only if a lot of crazy things happen do we have an outside chance of winning the title. To become champion, you have to be competitive on every circuit," he added.