Team boss Mattia Binotto on Monday rejected mounting speculation that Ferrari are favouring Charles Leclerc over Sebastian Vettel by giving him a faster car.
The pair finished six places apart in Sunday's Portuguese Grand Prix after which Vettel suggested that Leclerc had been driving a faster car.
Leclerc came home fourth and four-time champion Vettel 10th, a result that extended the German's season-long run of defeats by his team-mate as he seeks a dignified exit in his swan-song season with the Italian team.
"The cars of Seb and Charles are identical, no doubt," Binotto told Sky Italia.
"I sincerely hope that Sebastian can qualify better at Imola and show more of what he is capable of during the race.
"Charles is very good, but maybe you can expect more from the second driver."
Binotto's cryptic comment followed an equally enigmatic explanation from Vettel for his struggle for form.
"On the one hand, I'm satisfied because I had the feeling that I drove a good race," he told RTL.
"I had a hard time at the beginning, lost places and almost lost the car two or three times.
"After that I actually drove a good race.
"But, on the other hand, it's obvious that the other car is much faster. Where do I lose time? I have been biting my tongue all year long.
"Some idiot might never figure it out, but am I a complete idiot? I doubt it.
"At some point, you should be lucky and hit the limit. I never hit it and, if I do, then only with a lot of difficulty. On the other side (of the garage) it looks much easier."
A sparkling qualifying lap from Leclerc exemplified their differences as he claimed fourth on the grid and was half a second faster.
Vettel avoided making any direct accusations after the race, adding: "I have to think that we have the same car. I trust the people around me and in the garage."
To add to Vettel's current difficulties and much unwanted attention, he revealed also that he had sent Lewis Hamilton a pre-race text message, encouraging the six-time champion to claim a record 92nd race win.
"I'm happy for him," he said. "I think he deserves every single victory he had so I think the number speaks for itself. I'm sure he will hit 100.
"I texted him, before the race, to get 92. He achieved that and congratulations to him for that. You can't acknowledge that enough.
"Even when people say it's easy with that car, you have to have this kind of consistency over the years to do this."
Vettel was told before the season began that he was not being retained by Ferrari for 2021. Since then, he has agreed to join Racing Point, who will compete as Aston Martin next season.