Valtteri Bottas led seven times Formula One world champion team mate Lewis Hamilton in an ominous Mercedes one-two in final practice for the inaugural Qatar Grand Prix on Saturday.
Red Bull's championship leader Max Verstappen, who is 14 points clear of Hamilton with three races remaining in the Middle East, was third fastest but 0.341 seconds off the pace set by Bottas.
Bottas, who has taken three pole positions in the last four races and lapped fastest in Friday practice, put in a best time of 1:22.310 seconds and was 0.078 quicker than Hamilton.
Verstappen did fewer laps than Hamilton after losing time as Red Bull worked on his car's fluttering rear wing – a topical issue after the team made accusations about apparent wing flexing on Hamilton's Mercedes.
AlphaTauri's Pierre Gasly, who was consistently fast on Friday, was fourth with Verstappen's team mate Sergio Perez fifth.
Russian rookie Nikita Mazepin, who missed Friday's second session as his Haas team changed the chassis, had another frustrating session and again failed to set a time with the engine control unit and loom needing to be replaced.
