Fernando Alonso had been a pre-event favourite for victory at Silverstone, with the team having excelled on high-speed tracks so far this season.
But a lacklustre showing in qualifying, where he was only 10th fastest, hurt his chances of victory.
Although Alonso recovered to finish third and close down to the gap to championship leader Sebastian Vettel, Ferrari says it was the lack of pace that was a much bigger concern.
Domenicali said: "This weekend in terms of performance was not very good.
"We need to understand in these two or three days at home why.
"There is something that I would say is bigger than little details that caused us not to be better at Silverstone.
"This is the most important thing that we have to work on - understand and recover the performance."
Alonso's podium finish, allied to Vettel's retirement, meant that he cut the deficit to his rival to 21 points.
Domenicali said that the urgency to keep on delivering has increased though, because it now appears that Mercedes is going to be a regular threat for wins.
"We have seen that not only Red Bull now is strong, but Mercedes is very strong and they have solved their issue in terms of tyre degradation," he said.
"Now, if we want to win the championship, and that's still the objective we have, we need to improve the car."