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Lewis Hamilton ensured Mercedes ended pre-season testing with the fastest time on the final day in Bahrain.
With Felipe Massa having topped the timesheets on Saturday, his Williams team-mate Valtteri Bottas was quickest for the majority of Sunday's running until a late run from Hamilton on supersoft tyres saw him set a time of 1:33.278. That lap was still 0.020s shy of Massa's best this week, and came after Mercedes lost almost the whole morning session to a gearbox issue.
Bottas had to settle for second in the standings but managed to complete 108 laps as Williams showed impressive reliability. Bottas eventually stopped with a high-mileage engine failure during the final hour of running, causing the first red flag for a Williams all winter.
Fernando Alonso was third quickest in the Ferrari but was a second off Hamilton's pace and limited to 73 laps on the final day. Nico Hulkenberg and Jean-Eric Vergne both completed 74 laps as the latter got some more strong mileage in for Renault.
However, Lotus encountered more Renault-related issues as a power unit problem for Romain Grosjean forced the team to end running early for the fourth day in a row. Lap counts of 31, 31, 33 and 32 were consistent but leaves the team on the back foot heading to Melbourne.
Red Bull recovered from its “nightmare” day on Saturday by completing 77 laps, although Sebastian Vettel did have a spin at Turn 1 during the morning session which was attributed to a brake issue. The mileage will be crucial for the team after a tough winter as it starts its title defence in just two weeks time.
Vettel set the ninth quickest time with a late lap on soft tyres, putting him ahead of Jenson Button who managed just 22 laps for McLaren as a high-mileage engine failure consigned it to the garage for the majority of the day. Button was only able to complete one lap in the afternoon, and that was courtesy of an extra 25 minutes under the lights to make up for time lost to red flags during the week.
Sauber ended the day with its car returning on the back of the recovery truck, but completed a hugely impressive 177 laps as first Adrian Sutil drove in the morning before handing over to Esteban Gutierrez for the afternoon session