Bahrain GP F1 practice: Daniel Ricciardo fastest for Red Bull in FP1

Ricciardo leapt to the top of the leaderboard late in the opening 90-minute session at the Sakhir circuit to go three tenths clear of Valtteri Bottas.

Kimi Raikkonen lapped within a tenth of the lead Mercedes, with Sebastian Vettel just 0.012s further back in the daylight session.

As qualifying and the race will be held after sunset, teams were happy to wait to get proper running under way.

After initial benchmarks from the Force India drivers and Ricciardo's Red Bull, Mercedes developed a monopoly on the lead position for much of the session.

Hamilton and Bottas took turns in front with Hamilton's 1m32.532s the benchmark at the session's mid-point.

When running resumed after a short break, during which track temperature fell from 42C to 39C, Hamilton made a mistake on his next soft-tyre run.

Though he improved on his second flying lap Hamilton wound up 0.9s behind Bottas, who made the best of his new tyres and hammered in a 1m31.364s.

The two Ferrari drivers jumped into the chasm of lap time between the Mercedes drivers with 20 minutes remaining.

Red Bull's session was threatening to turn out miserably as Max Verstappen suffered a loss of power early on and Ricciardo stayed in the garage after his early foray on medium tyres.

Verstappen - who had to push his car back to the pits - did not emerge again, ending the session with just two laps completed and no time set as Red Bull changed his engine manifold assembly.

However, Ricciardo headed out in the final 20 minutes on soft tyres and made an immediate impact with a 1m31.060s, 0.304s quicker than Bottas.

Haas again emerged best of the rest behind the big three teams, with Romain Grosjean 1.4s off the pace in sixth and team-mate Kevin Magnussen also in the top 10 in ninth as both used supersoft tyres.

Pierre Gasly complained of traction problems early in the session but recovered to set the seventh-fastest time, 1.7s off the pace, with soft tyres on his Toro Rosso.

The Red Bull junior team has been given upgraded engine parts by Honda for this race after turbo and MGU-H problems were identified in Australia and was confident its car would suit the low-speed parts of Bahrain well.

Gasly outpaced several cars on supersofts, including the Renaults of Carlos Sainz Jr and Nico Hulkenberg (eighth and 10th) and both McLarens.

Charles Leclerc was another star performer on softs. Despite spinning early in the session the Sauber driver slotted into 12th, between the supersoft-shod McLarens of Fernando Alonso and Stoffel Vandoorne as they evaluated the upgrades that were originally planned for the opening race in Australia.

FP1 times