Fernando Alonso said there would be no quick end to Ferrari's troubles after a poor performance at their home grand prix in Italy.
Ferrari had their worst result of the season as the Spaniard retired with a hybrid system failure and team-mate Kimi Raikkonen finished ninth.
"The rest of the season is not going to be too different," said Alonso.
"After 12 or 13 races with difficulties it is not that the last six races will be magic races so we are prepared."
He added: "It is the way it is at the moment but we cannot do more than this."
Williams moved into third place in the constructors' championship, 15 points ahead of Ferrari, after their drivers Felipe Massa and Valtteri Bottas finished third and fourth in Italy.
Alonso's retirement was the first time he had not finished a race because of a car failure since he joined Ferrari in 2010.
Before the failure of his energy recovery system, he had been in a battle for the minor points positions with the McLarens, Red Bulls and Sergio Perez's Force India.
He said he thought he might have been able to beat Red Bull's Daniel Ricciardo for fifth had he not retired.
"With the first stint we were very competitive," he said. "Unfortunately we could not overtake because when four cars in a group the last three cars all open the DRS (overtaking aid) so I could not overtake anyone.
"We pitted and found ourselves behind the train of cars with no possibility of overtaking.
"And 30 laps from the end we tried to change a little bit the strategy approach and I backed off from the cars in front and then at that point the engine problem started."
Despite their poor result, Alonso hoped that Ferrari could be more competitive at the next races as their power disadvantage would not be as badly exposed as it was at high-speed Monza.
It was a tough first Italian Grand Prix for Ferrari team principal Marco Mattiacci, who is restructuring the team.
He said the support from the famously enthusiastic Italian fans, or tifosi, gave him "a lot of motivation to ensure this frustration is going to end".