Mercedes continued to hold a significant advantage over the rest of the field in the second practice session for the Bahrain Grand Prix as Ferrari encountered trouble with Sebastian Vettel's car.
After leading the first session by over half a second, Nico Rosberg also topped the times in the evening, albeit with a smaller advantage of 0.241s over team-mate Lewis Hamilton. Once again, Hamilton was marginally quicker than Rosberg in sector one but lost most of his time in the final sector, where Rosberg was over 0.2s faster. Mercedes' closest rivals remained over a second off the pace, with Jenson Button setting the third fastest time with an impressive lap in the McLaren, 1.280s off Rosberg's best effort, and Max Verstappen fourth fastest, 1.405s slower than the lead Mercedes.
Ferrari's threat failed to emerge, with Kimi Raikkonen fifth fastest, 1.451s off Rosberg, and Vettel a further two tenths adrift in sixth after a mistake on his lap on fresh super-soft tyres. Any hope of a late improvement for Vettel was dashed when his car lost drive on the fifth lap of a soft-tyre stint, forcing him to park his Ferrari at the side of the circuit. As the car was lifted away there appeared to be damage to the left rear, with Vettel radioing back to the pits to confirm the problem.
Daniil Kvyat was seventh fastest for Red Bull ahead of Valtteri Bottas in eighth for Williams, team-mate Daniel Ricciardo in ninth and the second Williams of Felipe Massa in tenth. Fernando Alonso's replacement Stoffel Vandoorne was 11th fastest as his F1 debut continues, with a lap time 0.718s off team-mate Button.
Haas continued to show impressive pace, with Esteban Gutierrez 12th fastest, but his session ended with a wisp of blue smoke from the rear of the car. Team-mate Romain Grosjean also suffered from a reliability issue after experiencing a front wing failure at Turn 13, which resulted in debris being left across the track. He was able to stop the car in the ample run off area and returned to the pits where he remained for the rest of the session.