Austin's Circuit of the Americas marks the start of the season's final quarter, the first of three remaining Saturday sprints as well as the first race since McLaren secured the constructors' championship for the second year running.
Australian Piastri leads his British rival by 22 points with six of 24 rounds remaining while Red Bull's Verstappen is 63 points off the lead.
If the four-time world champion's task sounds more than a long shot, the fact remains that he has clawed back 41 points from Piastri in his last three outings and also beaten both McLarens in those three races.
Austin is very much to Verstappen's liking, the Dutch driver winning there in 2021, 2022 and 2023 before Ferrari enjoyed a one-two last year with Charles Leclerc and Carlos Sainz.
Verstappen still won the sprint in 2024, however, and can never be counted out - arriving this time after four successive podiums.
"While we’d like it (the championship) to solely come down to our two guys, Max is still very much in the game," said McLaren boss Zak Brown after the team title was secured in Singapore.
There was plenty of talk after that race of the gloves being off between the McLaren pair in their duel for the championship but team management emphasised that so-called 'Papaya Rules' still apply.
"Our strategy isn’t going to change because we’ve won the constructors’, we’re going to approach the remaining race weekends in the same way we’ve approached every one before it," said Brown.
That means equal opportunities and a 'race but do not collide' philosophy.
Norris, who took pole position in Austin last year but finished fourth with Verstappen third, would have the most to lose if he and Piastri do make contact since the Briton needs to make inroads into the Australian's advantage.
Piastri's best result in Austin is fifth last year, after failing to score in the sprint when he finished 10th from 16th on the grid, and this time he risks a third successive race off the podium.
In 2023 he retired following a collision with Alpine's Esteban Ocon. Norris was second that year, when he was also fourth in the sprint.
Ferrari are the only top four team yet to win this season but seven-time world champion Lewis Hamilton, who replaced Sainz at the end of last year, is a five-time winner in Austin.
The 40-year-old returns this time still searching for his first podium with the Italian team and now holding the unwanted record of 18 starts for Ferrari without once finishing in the top three.
George Russell, winner for Mercedes in Singapore, will be chasing a third triumph of the season with a new contract for 2026 freshly inked, keeping him alongside Italian teenager Kimi Antonelli for at least another year.
