Formula One world champions Mercedes see resurgent Ferrari as a genuine threat this season.
Drivers champion Lewis Hamilton and his team mate Nico Rosberg revealed their fears about the Italian manufacturer in the build-up to this weekend’s Japanese Grand Prix.
Sebastian Vettel won in Singapore on Sunday for his third victory in 13 races for the Prancing Horse
This prompted the Mercedes team-mates to agree that their Ferrari rivals were firmly back on their radar.
"They are a threat and we do take them very seriously," said Rosberg, who is second in the championship - 41 points behind Hamilton but now only eight clear of Vettel with six races remaining.
"They have been a threat at various times throughout the whole season."
Hamilton, who failed to finish in Singapore in his first retirement of the year, said he had never ruled Ferrari out of the equation.
"How seriously I take it (the Ferrari threat) hasn't changed since Malaysia," said the Briton, winner of seven races this year with 11 poles in 12 races until Singapore when Vettel was fastest on Saturday and Sunday.
Hamilton said Mercedes had in-depth post-Singapore analysis of how Vettel was a second and-a-half faster than their closest rivals.
The South East Asian street circuit is slow and twisty, unlike Suzuka in Japan, which has some fearsome high-speed corners, and the race run at night in high humidity.
"I can't tell you what the team have come up with but they have come up with a lot of solutions; a lot of reasons for it being the way it was," said Hamilton.
"The majority of them believe that at least one of the many reasons they came up with had a domino effect. So I'm confident that it's been understood but they will still continue to do analysis for sure."
Vettel, who has now won as many races in his debut season with Ferrari as Michael Schumacher did in his first year at Maranello in 1996, told a separate news conference that he expected Mercedes to be faster in Suzuka.
"In a way it was a big surprise to see Mercedes struggling, which I don't expect to be the case here. Again, it would be a big surprise," said the German.