British driver Lewis Hamilton clocked the fastest time during the second day of testing on Tuesday at the Sakhir circuit where he won the Bahrain Grand Prix at the weekend.
Three of the five world champions still competing -- England's Jenson Button (McLaren), Finland's Kimi Raikkonen (Ferrari) and Germany's Sebastian Vettel (Red Bull) -- did not take part in the testing which allowed certain stables to use their reserve drivers and Pirelli to test their new tyres.
Hamilton's Mercedes teammate and championship leader Nico Rosberg clocked the fastest time in the day's first practice session.
Other two-day practice sessions will take place throughout the season, on the Tuesday and Wednesday, after certain Grand Prix.
1. Lewis Hamilton (GBR/Mercedes) 1min 34.136sec (120 laps), 2. Jean-Eric Vergne (FRA/Toro Rosso-Renault) 1:35.557 (63), 3. Kevin Magnussen (DEN/McLaren-Mercedes) 1:36.203 (26), 4. Sergio Perez (MEX/Force India-Mercedes) 1:36.586 (62), 5. Daniel Ricciardo (AUS/Red Bull-Renault) 1:37.310 (65), 6. Jules Bianchi (FRA/Marussia-Ferrari) 1:37.316 (93), 7. Giedo van der Garde (NED/Sauber-Ferrari) 1:37.623 (77), 8. Fernando Alonso (ESP/Ferrari) 1:39.912 (12), 9. Marcus Ericsson (SWE/Caterham-Renault) 1:39.263 (66), 10. Felipe Nasr (BRA/Williams-Mercedes) 1:39.679 (64), 11. Romain Grosjean (FRA/Lotus-Renault) 1:40.183 (16)