Red Bull's triple world champion Max Verstappen won a US Grand Prix sprint race from pole position on Saturday with old foe Lewis Hamilton second for Mercedes.
The Dutch 26-year-old finished 9.465 seconds ahead of Hamilton, who seized second at the start and gave chase but then dropped back, in the 19-lap stand-alone race at Austin's Circuit of the Americas.
Ferrari's Charles Leclerc took third after being passed by Hamilton at the start of a race that paid points to the top eight finishers.
The main event at the Texas track is on Sunday with Leclerc starting on pole position and Verstappen chasing his 50th grand prix win from sixth on the grid.
Dominant Red Bull and Verstappen have already secured both the constructors' and drivers' world championships with a fistful of races to spare.
Red Bull have also won 16 of 17 races this year.
Verstappen chopped Leclerc aggressively towards the pitlane exit on the opening run to turn one, with Hamilton forced beyond the track limits but making the pass on the Ferrari without penalty.
In the early laps, Verstappen and Hamilton ran close enough for the Briton to have DRS (drag reduction) but then the Red Bull pulled away.
"It was quite tight. Luckily there was a lot of space going into Turn One, so that helps," said Verstappen, the first driver to win three sprints in a single season.
"After that we could do our own race and control the pace a bit. I had a bit of fun at the end, pushing a bit more."
McLaren's Lando Norris finished fourth, just running out of time to pass Leclerc, with Red Bull's Sergio Perez fifth and Ferrari's Carlos Sainz -- the only driver starting on the quicker wearing but faster soft tyres -- sixth.
Pierre Gasly was seventh for Alpine and George Russell took the final point for Mercedes.