Germany's Nico Rosberg stayed ahead of team mate Michael Schumacher to put Mercedes on top of the timesheets in practice for the Formula One season-opening Bahrain Grand Prix.
After compatriot Adrian Sutil had stolen some of the returning seven-times champion's limelight in the first session with the quickest time for Mercedes-powered Force India, Rosberg went faster in the afternoon.
The son of former champion Keke lapped the newly extended Sakhir circuit in one minute, 55.409 seconds, nearly half a second quicker than his 41-year-old team mate in third place.
McLaren's Lewis Hamilton was second, running faster than team mate and reigning champion Jenson Button who had been ahead in the morning.
Mercedes engined cars filled the top four slots.
Spain's double world champion Fernando Alonso limbered up for his Ferrari race debut with the second best time in the first session and then ninth after lunch.
While practice times can be misleading, with drivers trying out different set-ups and running with varying fuel loads, all eyes were on Schumacher's pace after an absence of three seasons.
With Mercedes returning as a works team for the first time since 1955 after taking over champions Brawn, the former Ferrari great was 10th in the morning and more than 0.4 seconds slower than Rosberg.