Mercedes's two drivers have admitted that their 2017 car is difficult to drive.
Having the more obvious struggle recently is Valtteri Bottas, whose pace relative to championship leader Lewis Hamilton has been starkly off.
"I think Lewis has been able to extract a little more with the compromises we've been needing to do in some circuits to get it into the right window," said the Finn at Suzuka.
With Ferrari and perhaps even Red Bull sometimes speeding ahead in terms of pure pace recently, team boss Toto Wolff has called Mercedes's 2017 car a "diva".
"I didn't say that. Toto did," Hamilton told reporters in Japan.
"It's stubborn, but it's cool because I'm stubborn."
Hamilton said that he expected Malaysia to suit the Mercedes last weekend, and the team now has higher confidence that Suzuka will be a good circuit for the car.
"This deep into the season, I still have no idea where it's going to be good, where it's going to be great, where it's going to be a real struggle," he admitted.
Mercedes lead second-placed Ferrari by 118 points heading into the Japanese Grand Prix.
