Sebastian Vettel put Ferrari on top during the first practice session for the Bahrain Grand Prix as team-mate Kimi Räikkönen was stranded by an engine issue.
In exceptionally hot weather at Sakhir, with air temperatures approaching 40°c, Vettel clocked a 1:32.697 on Soft tyres, to finish four-tenths clear of Red Bull’s Daniel Ricciardo.
However, while Vettel finished quickest, Räikkönen had to sit out the final 50 minutes of the session, losing substantial track time, after he slowed with smoke trailing from the rear of his SF70-H.
Räikkönen parked along the straight between Turns 13 and 14 and walked back to the paddock, with Ferrari later confirming that an overheating turbo was the reason for his stoppage.
Max Verstappen finished third for Red Bull, 0.869s behind Vettel, as Mercedes opted not to set rapid times in the unrepresentative conditions.
Lewis Hamilton rounded out the top 10, 1.939s off the pace, while team-mate Valtteri Bottas placed 14th, a few tenths further back.
Sergio Pérez claimed fourth for Force India, in front of Williams pair Felipe Massa and Lance Stroll, the Brazilian’s session coming to a dramatic end when he suffered a brake failure at Turn 13.
Massa was pitched into a spin but came to a safe halt in the run-off and was able to slowly recover to the pit lane.
Esteban Ocon, Fernando Alonso, Romain Grosjean and the aforementioned Hamilton completed the top 10.
McLaren's Stoffel Vandoorne stopped on track exiting Turn 10 with 20 minutes remaining, amid a suspected loss of power, leaving him unable to complete the entire session.
Pascal Wehrlein returned to Formula 1 action with Sauber and finished 18th, within a tenth of a second of team-mate Marcus Ericsson.
