Mercedes continued where they left off after winning the Bahrain Grand Prix as Nico Rosberg set fastest time on the first day of the in-season test at the Sakhir circuit.
The German completed 121 laps and set a benchmark 1:35:697, some half a second quicker than 2nd placed Nico Hulkenberg in the Force India.
There were problems for Ferrari and Lotus as Fernando Alonso and Pastor Maldonado both stopped on track; Lotus never managed to get back out and their tally for the day was just 16 laps.
Robin Frijns did the honours for Caterham, while Sauber gave Sergey Sirotkin his first taste of F1 machinery as he completed 76 laps and logged a 1:39:023.
Testing continues on Wednesday at Sakhir.
CLASSIFICATION – TIMES – DAY ONE – Bahrain In-Season Test 8th Apr 2014