Lewis Hamilton finished third as Sebastian Vettel set the pace in final practice for the US Grand Prix.
Hamilton will be crowned world champion for a fifth time in Austin on Sunday if he outscores Vettel by eight points.
Ferrari’s Vettel was penalised with a three-place grid drop for the race after failing to slow sufficiently under red flags in practice on Friday.
But the German was quickest at the Circuit of the Americas in the final running before qualifying. The highest he can start Sunday’s race, however, is fourth.
Mercedes driver Hamilton was fastest in both rain-hit practice sessions on Friday, but Ferrari held the edge in the dry.
Vettel edged out his team-mate Kimi Raikkonen, with Hamilton just 0.073 seconds off the pace.
Valtteri Bottas finished fourth in the sister Mercedes, 0.7 sec slower than Vettel. Max Verstappen finished fifth for Red Bull ahead of Daniel Ricciardo.
Double world champion Fernando Alonso, who is retiring at the end of the year, was last in his McLaren.