Ferrari's Sebastian Vettel continued his reign in the desert, ending Friday's free practice in Bahrain on top of the timesheets.
Vettel's time was surprisingly slower by three tenths compared to 2016's best FP2 time. Vettel ended the session less than a tenth of a second clear of Mercedes' Valtteri Bottas and Red Bull's Daniel Ricciardo.
However there was a scare for the four-time world champion. His car went into a total shutdown without warning, which left him stuck in fourth gear and without power midway through the 90-minute session. Vettel put the car into neutral and freewheeled his way down the hill and onto pit lane for repairs.
Second practice had got underway as the sun set over Sakhir and the sparkling floodlights took over. That made conditions for FP2 much closer to those the drivers will face in qualifying and Sunday's race than they had been earlier.
Romain Grosjean was the first to set a time in the Haas, soon bettered by Vettel who immediately picked up where he had left off in FP1. The two Mercedes drivers also briefly went fastest before Kimi Raikkonen put Ferrari back on top, the team having swiftly completed repairs to his SF70H after its FP1 breakdown.
Vettel lowered the bar further, this time by nine tenths with his next lap clocking in at 1:31.310s half an hour into the session. Hamilton's initial attempt to respond was thwarted by Nico Hulkenberg's slow-moving Renault, which caused the Mercedes to go off-track in turn 9 in avoidance. The incident was subsequently earmarked for post-session review by the race stewards.
With attention turning to race simulations, Vettel's top time continued to stand despite improved efforts from Bottas and Ricciardo which put them ahead of Raikkonen and Hamilton. Following his shutdown scare, Vettel was quickly back out on track although he subsequently reported a brake alarm. The team appeared unconcerned by this news and allowed Vettel to keep pushing.
Earlier, Carlos Sainz had triggered a virtual safety car when his Toro Rosso died a smoky death in sector 2 on his sixth lap of the evening. He took no further part in the session after immediately jumping out of the car.
Max Verstappen had a lengthy spell in the garage, when Red Bull had to make repairs to the underside of his car. The RB13 had sustained damage after running over the T-wing of Bottas's Mercedes, which had broken off during an earlier flying lap.
Stoffel Vandoorne also lost running time early in the session, as McLaren finished off the engine change necessitated by the MGU-H failure in FP1. His session was then further curtailed with a further power unit issue after he had managed to complete just eight laps.
In the final minutes of the session, Lance Stroll reported overheating in the cockpit of the Williams. However the team still completed a final pit stop practice before the FW40 was wheeled back into the garage and Stroll allowed to climb out.
Free Practice 2 results