Nico Rosberg says teams racing in F2 and F3 manage their pitstops and strategy better than Ferrari, a scathing criticism that did not go down well with Scuderia boss Mattia Binotto.
Sunday's Dutch Grand Prix was a rather chaotic affair for the Italian outfit.
Charles Leclerc and Carlos were comprehensively outpaced by Red Bull and Max Verstappen at Zandvoort, but while the Monegasque was able to score a third-place finish at the end of the day, Sainz's race was undone by another series of clumsy missteps by his Ferrari crews.
The Spaniard's first setback occurred when the Scuderia fumbled its pitstop when a left-rear medium tyre wasn't where it was supposed to be.
Any hope of Sainz recovering from the mistake was put to rest during his second stop when the #55 Ferrari was released in the path of Fernando Alonso's Alpine, a miscue that earned Sainz a five-second penalty.
The glitches were the latest in a series of blunders and mismanagements that have cost Ferrari a boatload of points this season.
Sky F1 consultant Nico Rosberg didn't hold back his criticism of Ferrari's operational errors and Binotto's opposition to change.
"Oh my goodness," said the 2016 F1 World Champion. "Mattia Binotto keeps saying 'No, no, we don't need to make any changes, everything is going well'. When is the day coming?
"It's not possible – even Formula 2 teams or F3 teams do a better job at their strategy and pitstops than Ferrari.
"You go to the pits and there's no tyre there in a normal race? At some point they really need to start making some changes."
©Ferrari
Rosberg's comments were submitted to Binotto who brushed them off, insisting it was way too easy to criticize from the comfort of one's home.
"First, I think it is so easy to speak when you are outside [of the paddock]. It is easy to criticise," he said.
"But we will not change people: that is my answer to Rosberg. We have got great people and it has been proven that what is more important in sport is stability and that we make sure we are improving day-by-day and race-by-race.
"We have got great people in the team and I have no doubt on that. It takes years and experience for all teams to be at the front, and I think there is no reason why it should be different for ourselves."
Binotto admitted that Ferrari's late call to Sainz to pit set up the team's missing tyre issue.
"Yes it was a very late call to react to Lewis [Hamilton] with Carlos. It was too late a call," he said.
"But I know as he [Rosberg] should know as well because he is an experienced driver, that it is a lot easier to address those type of problems rather than the performance.
"The performance is what counts the most today in my view."
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