Sergio Marchionne has admitted that Ferrari's performance at home at Monza was "embarrassing".
As Mercedes drove to a one-two, the team's drivers admitted that they turned down their engines while easily beating Ferrari's third-placed Sebastian Vettel to the podium.
"Mercedes power is definitely better than Ferrari power," said new championship leader Lewis Hamilton on the podium, to the jeers of the Tifosi.
However, just a week ago at Spa, the 2017 Ferrari actually looked quicker than the Mercedes, and prior to that Vettel led an all-red one-two in Hungary.
President Marchionne said at Monza: "If I look at the difference between Mercedes and Ferrari today, it's embarrassing.
"But our goal has not changed. What the Tifosi saw today was simply not the real Ferrari.
"Something has gone wrong."
Indeed, amid Mercedes's Monza dominance, team chairman Niki Lauda admitted that Ferrari should "easily win" on the tight and twisty Singapore layout in a fortnight.
Marchionne agrees: "Yes, I think so.
"But that does not change that a week ago we were very close to victory and perhaps had even the best car. Then something happened.
"For the first time this season we were below expectations in the race, so obviously we have work to do. But while Monza is Monza, the world championship is still long.
"But the others were almost one second ahead of us, and that's impossible. That is not Ferrari."
Mercedes have a 62-point lead over Ferrari following the race at Monza.
