Daniel Ricciardo gave Red Bull a boost by posting the fastest time in the first practice session for the Bahrain Grand Prix on Friday.
The Australian clocked 1 minute, 31.06 seconds on the 5.4km desert circuit.
He was 0.3 seconds quicker than Mercedes driver Valtteri Bottas and 0.4 ahead of Ferrari's Kimi Raikkonen, whose teammate Sebastian Vettel placed fourth.
World champion Lewis Hamilton was fifth. The British driver had a tricky session, twice taking his Mercedes too wide on corners and finishing more than one second behind Ricciardo.
Earlier, Ricciardo's teammate Max Verstappen's car lost power and ground to a halt on the track.
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The Dutch driver got out and helped stewards wheel the car back to the team garage.
It was another blow for Verstappen, who spun his car early into the season-opening Australian GP two weeks ago. He finished in sixth place.
Vettel won in Melbourne, profiting from an error by Mercedes to finish ahead of Hamilton.
There is a second practice later Friday, when cooler temperatures will match those in Sunday evening's race.
