LONDON (REUTERS) - Valtteri Bottas led seven-time Formula One world champion teammate Lewis Hamilton in an ominous Mercedes one-two in final practice for the inaugural Qatar Grand Prix on Saturday (Nov 20).

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 of a second off the pace set by the Finn.

Bottas, who has taken three pole positions in the last four races and lapped fastest in Friday practice, put in a best time of 1min 22.310sec and was 0.078 quicker than the Briton.

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 teammate 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.

Qualifying for the floodlit night race is scheduled to start at 1400 GMT (10pm Singapore time).

F1 Qatar Grand Prix

Qualifying: Singtel TV Ch112 & StarHub Ch201, 9.55pm