Flavio Briatore insists Ferrari has made no progress in 2015.
Several times recently, the Italian has defended Fernando Alonso’s decision to leave Maranello just as it appeared to bounce back into contention.
Briatore, who is still involved in Alonso’s management, said: "Look, I don’t deny that Ferrari has become the second force this season. It’s true."
But he told the Ferrari media insider Leo Turrini’s blog that it is not because Ferrari has dramatically improved, but because its rivals "disappeared".
"Red Bull has the disastrous Renault power unit," said Briatore, "while Williams is penalised by the engine Mercedes makes available to it. It is clearly not on the same level as the one used by (Lewis) Hamilton and (Nico) Rosberg.
"The others fell back, Ferrari remained firm but they did not close the gap that Mercedes had.
"If you look at the gap (Sebastian) Vettel had against the Mercedes at the end of the race in Barcelona, you’ll see it’s more or less the same that Alonso had last year.
"Same with qualifying in Monaco if you compare what Vettel (2015) and Alonso (2014) did," Briatore added.
"If you say that Ferrari has already won a grand prix, I say ’congratulations’ but it was because of a strategy error by Mercedes, just as Vettel’s second place in Monaco was as well."
Briatore said he is making his comments about Ferrari not to be "hostile" but to "say it how it is".
Finally, the 65-year-old Italian said he has no interest in taking over from Bernie Ecclestone as F1 chief executive.
"The way I see it," said Briatore, "the future of formula one is very grey.
"We have absurd rules, we hear engineers tell drivers to save tyres, save engines, save fuel — this is racing in the new millennium?" he wondered.