Ferrari may have taken the leap ahead they were seeking after introducing a revised turbo design for the Canadian Grand Prix.
Sebastian Vettel split the two Mercedes cars in Friday practice in Montreal, with the German remarking: "I hope not only to split them on Sunday, but to be in front of them."
Ferrari senior engineer Jock Clear confirmed that the new turbo, updated so that the recovered energy can be deployed more often, did "what it said on the tin".
However, both Vettel and teammate Kimi Raikkonen were still grumbling about the handling, indicating that Red Bull are still in the battle.
"I'm sure we can be in front of them again with the right lap [in qualifying]," said Daniel Ricciardo.
However, his teammate Max Verstappen acknowledged: "I think Ferrari is stronger than they were in Monaco."
Ferrari's Vettel is quoted by La Gazzetta dello Sport as saying: "Are we stronger [than them]? I don't know, but the good news is that the new parts seem to work."
Vettel and Raikkonen are fifth and fourth in the standings ahead of the Montreal race.