Ferrari will investigate why it has surrendered ground to Red Bull and Mercedes in recent races.
The Scuderia had started the season as title protagonists with blistering qualifying pace and good tyre degradation compared to Red Bull.
But the Milton Keynes-based team stole a march mid-season as Ferrari blundered and whilst pace during that difficult period remained strong, performances have dropped off in the two races since the end of the summer break.
Asked whether he believed Red Bull had improved or his own team had taken a step backwards, team principal Mattia Binotto said: "Honestly, I don't know right now.
"These are answers I don't have. It is not only Red Bull that's fast, Mercedes is ahead of us on race pace.
"So maybe it is more ourselves that have gone backwards. The reason why? Something we need to look at.
"It is three races we have not performed on a Sunday like we should and no doubt, it is not only Red Bull but also Mercedes that is faster than us."
Friday performance masked issues
Ferrari had topped second practice at Zandvoort before slowly sliding behind Red Bull and eventually Mercedes in the race, Charles Leclerc finishing behind Max Verstappen and George Russell on the podium.
But insisting the times on Friday only masked issues, Binotto explained: "If you heard the two drivers early on Friday, they were not too comfortable with the car and the car balance, they felt it was tricky to drive.
"After we worked Friday night, on Saturday [they were] a bit more comfortable and happier with the car but the fact the car was already tricky on Friday was showing that we were not at our best.
"It is always difficult to compare the data on Friday, we can only judge to ourselves and if we judge to ourselves, the drivers were not comfortable, the car was tricky to drive so we were not right already on the Friday."