The battle at the top between Norris and Piastri is on a knife-edge with four rounds remaining, with the Briton a point clear of the Australian.
Norris has momentum, despite insisting he does not believe in that, and has beaten his teammate in the last five races - although they collided in the most recent sprint in Austin.
But Piastri showed signs of a comeback and return to form in the Mexico race, if not qualifying, and with a Saturday sprint also in the mix in Brazil and paying extra points the gap is set to widen one way or another.
"Brazil is a great opportunity to score some big points, especially with the sprint race. There is everything still to play for, and preparation for this weekend has been very productive," said the Australian.
Big points up for grabs
Verstappen will be looking to make inroads of his own with a bumper 33-point haul to be won from the weekend's two races.
Red Bull's four-times world champion is 36 points behind Norris, after being 104 adrift of then-leader Piastri at the end of August, and Sao Paulo's bowl-like Interlagos circuit is an old favourite.
The Dutch driver - who has family connections to Brazil through his partner Kelly Piquet, daughter of triple champion Nelson - is going for his third successive win there and fourth in all.
He is also the acknowledged king of the sprints, even though Norris won last year's in Sao Paulo, with more wins - 13 of 22 - in the short format than anyone.
"It can rain heavily there so you can have quite crazy races, especially last year's race where we won after qualifying 17th, which was an emotional win and an important moment in the championship," he said.
Current forecasts suggest it could be a wet Saturday - the kind of conditions Verstappen thrives in - but a cooler, dry Sunday.
Ferrari's Lewis Hamilton is also a three-time winner at Interlagos and proud to be an honorary Brazilian.
The Briton has yet to stand on the podium since he joined Ferrari and where better than the circuit where he took the first of his seven titles with a last-gasp overtake in 2008 as a McLaren driver?
Ferrari have not won there since Sebastian Vettel triumphed in 2017, however.
"We come to Brazil with a positive attitude, off the back of two solid weekends in Austin and Mexico, where we maximised the potential of the car," said team boss Fred Vasseur.
"The goal now is to keep this momentum going, focus on execution, and be ready to react to whatever weather conditions we encounter in Sao Paulo."
The constructors' championship has already been won by McLaren but the battle for second is too close to call, with Ferrari only a point clear of Mercedes and Red Bull a further nine adrift.
Brazil will have a driver to cheer for the first time since 2017, with Gabriel Bortoleto making his home debut for Sauber while an influx of Argentine fans is to be expected as Franco Colapinto returns with last-placed Alpine.
The Renault-owned team had a double podium to celebrate in Brazil last year, with Esteban Ocon and Pierre Gasly second and third, but their current form has been dire, with fewer points from 20 races this year than in that one.