World champion Max Verstappen limbered up for the first qualifying session of Formula One's new era by pipping Ferrari's Charles Leclerc to the fastest time in Saturday's final practice session for the Bahrain Grand Prix.
The Dutchman hustled his Red Bull around the 5.4-km Sakhir track in one minute 32.544 seconds, with Leclerc hot on his heels with a time just 0.096 seconds slower.
Mexican Sergio Perez was two-tenths of a second off his Red Bull teammate's benchmark in third.
Red Bull and Ferrari have been hyped up by rivals as the favourites going into Sunday's season-opener, which will usher in one of the most radical rules overhauls in F1 history aimed at improving the racing spectacle.
Mercedes, gunning for a record ninth successive constructors' crown, have, in comparison, struggled to squeeze the speed from their new challenger, with Lewis Hamilton warning fans not to expect him to be in the fight for the win on Sunday.
The seven-time champion, the most successful driver at the Bahrain track with five wins, was only sixth, half a second off his Red Bull rival's pace.
New teammate George Russell was fourth 0.391 seconds off Verstappen's best.
F1 returnee Kevin Magnussen, replacing sacked Russian Nikita Mazepin, put the Haas team in a promising seventh.
Former Mercedes racer Valtteri Bottas was eighth ahead of Alfa Romeo teammate and Chinese rookie Guanyu Zhou.
Canadian Lance Stroll rounded out the top 10 in his Aston Martin.
Nico Hulkenberg, standing in at Aston Martin for Sebastian Vettel, who has been sidelined by COVID-19, was 12th.
This weekend, Australian Daniel Ricciardo, back in the car having just recovered from COVID, was 15th for McLaren.
Saturday afternoon's hour-long session was largely incident-free. Leclerc survived a spin while Ferrari came under investigation for releasing Carlos Sainz into the path of compatriot Fernando Alonso's Alpine in the pitlane.