Sebastian Vettel is confident Ferrari can get a postive result in Brazil. Photo: Jerome Miron/USA TODAY Sports

Sao Paulo  Ferrari arrive at the Formula One Brazilian Grand Prix looking to bounce back from both a disappointing race in the United States and allegations of cheating - that they strongly denied.

"I think overall it's been a good hunting ground for us and hopefully it will be like that again this weekend," their driver Sebastian Vettel said in the team preview for Sunday's race at the classic Interlagos circuit in Sao Paulo.

Vettel is the more likely Scuderia contender on the 90th anniversary of the team being formed given Charles Leclerc will "drop at least 10 grid places - but quite likely a lot more," according to the F1 website, for using a new power unit.

Should Vettel win he will move level with Michael Schumacher on four Brazilian triumphs. World champion Lewis Hamilton has two, the same as his hero and local icon Ayrton Senna.

Ferrari experienced a sudden drop in performance at the US Grand Prix, something Red Bull's Max Verstappen claimed was related to the governing FIA issuing a clarification on how fuel could be delivered.

"That's what happens when you stop cheating, of course," he told Dutch television.

Leclerc branded the accusations "a joke" as the young drivers, widely considered potential future world champions continued a rivalry which has bubbled this season with on-track clashes.

"We should be back to our normal performance level and show some fighting spirit to finish the season on a high note," said team principal Mattia Binotto.

"That will be important in order to confirm we are making progress with our car and to take some of that momentum into the winter work."

Mercedes, having secured a sixth successive drivers' and constructors' double, will be without team chief Toto Wolff who is staying in Europe to "focus on other open topics."

Hamilton and Valtteri Bottas will definitely finish first and second in the standings but Wolff insisted: "We have two races to go in the 2019 season and we want to end this season on a high."

On occasion Hamilton has eased off with the title won but celebrated championship number five by winning in Brazil last year. Victory again would take him to 84 career race wins and within seven of Schumacher's all-time best of 91.

The circuit at Interlagos is a relatively short 4.309 kilometres meaning the margin for error in Saturday's qualifying is small.

"We have generally not had the fastest car on Saturdays since the summer break, but we were able to take pole in Austin and will try to fight for a front row start again at Sao Paulo," said Wolff.

Ferrari have claimed six pole positions from the last eight races but Red Bull will expect to be competitive again having been unlucky not to win with Verstappen 12 months ago.

Verstappen could yet catch Leclerc for third in the standings but is fending off Vettel from behind. His team-mate Alexander Albon will also be on a high having confirmed his race seat for next season.

While that next term will already loom large in the thoughts of the 'big three' teams, the midfield pack of McLaren, Renault, Racing Point and Toro Rosso have no such luxury.

Only 57 points separates McLaren in fourth from Toro Rosso's seventh in the constructors' standings and with each place worth millions in prize money, there will be no let up.