chinese grand prix , renault suffered two blown engines as first red bull 's daniil kvyat was forced out of the race , followed late on by toro rosso 's max verstappen .
it was yet further embarrassment for renault who are under pressure to perform after red bull 's billionaire benefactor mateschitz threatened to pull out of formula one unless the french manufacturer raised their game .
red bull team principal christian horner has been critical of renault this season .