Red Bull should be back to their dominant best in Japan this weekend after suffering their first defeat of the season in Singapore last Sunday, Mexican driver Sergio Perez said.

The Formula One champions had won 15 races in a row until then but they return to the figure-of-eight Suzuka circuit with every expectation of wrapping up the constructors' title with six rounds to spare.

"This track is very different so there should not be a reason why not to be strong in Suzuka," Perez told reporters at the Honda-owned track on Thursday. "Actually, this should be one of the best circuits for us."

Perez, second overall but a massive 151 points behind teammate and double world champion Max Verstappen, said Red Bull still did not know exactly why they had struggled so much in Singapore.

Verstappen, winner of 10 races in a row until that point, finished fifth after starting 11th at Marina Bay while Perez ended up eighth.

"We obviously have some good idea on how we prepare the weekend and the misinformation we had and where things got wrong," said the Mexican.

"It's something that we will keep internally but there's some good indications that we probably approached the weekend with the wrong setup."

Perez said the car had felt good on the Suzuka layout in the simulator, whereas Singapore had felt bad already before last weekend.

"Hopefully it aligns well and it can be a good track for us," he added.

Red Bull have denied any impact on their form of a recent FIA directive clamping down on flexible bodywork, and Mercedes' seven-time world champion Lewis Hamilton expected Red Bull to be hard to beat again.

"I would think that if they're not 30 seconds ahead like they have done in the past then something's up," laughed the Briton, who was third in Singapore.

"Their car should be phenomenal here. They've been phenomenal all year long, they've aced pretty much every circuit.

"It's going to be great to watch that car in general. Normally you would come here and it's beautiful to watch the laps they do because the team as a whole and the drivers are doing an amazing job with the package they have."

Hamilton doubted Mercedes would have the same level of performance as Singapore but hoped they were not too far off Red Bull.