Leclerc was imperious in leading Carlos Sainz to a Ferrari one-two once he had moved into first place, but the drama was all behind him.
The title battle between Max Verstappen and Lando Norris erupted in controversy at the United States Grand Prix after the McLaren driver was penalised for passing his rival for third place off the track.
Norris finished third after passing Verstappen around the outside at Turn 12 with four laps to go, only to run off the track on the exit of the corner.
Norris chose not to give the place back, while Verstappen complained he had to, and the stewards agreed with the Dutchman.
They handed Norris a five-second penalty and as he had pulled out only a 4.1-second lead once in front, he was dropped back to fourth place, one behind the Red Bull driver, in the results.
Verstappen has therefore extended his championship lead to 57 points with five races to go and 146 points still available.
Piastri was a further 1.5s behind Norris in the final race times to collect fifth, 34 seconds clear of George Russell – who converted a pitlane start in the wake of his qualifying crash into sixth, thanks to a late pass on Sergio Perez.
Nico Hulkenberg took eighth to ensure Haas could put two points between it and RB in the fight for sixth in the constructors’ championship, although Liam Lawson celebrated his return to F1 with ninth place with the contra-strategy of starting on hards.
Franco Colapinto collected the final point having also benefitted from starting on the hard tyre.
