Nico Rosberg on top again in second Bahrain Grand Prix practice

The German clocked a 1m31.001s on the super-soft tyres, nearly 1.6 seconds quicker than last year's pole position time, to finish 0.241s clear of Hamilton.

Rosberg had earlier led another Mercedes one-two in first practice and continued the team's dominance in the second session as the sun set and the floodlights flickered on at the Bahrain International Circuit.

Jenson Button showed surprising form with McLaren as he became the Mercedes' closest challenger but he was 1.280s off the pace with Toro Rosso's Max Verstappen fourth, a tenth further back.

Mercedes started on the softs with Rosberg going quickest with his first run, 0.210s faster than Hamilton managed moments later.

Sebastian Vettel slotted into third on the softs, 0.477s off the pace, but made two mistakes on his super-soft run and failed to improve.

The German's session came to a premature end when he stopped out on track with 15 minutes remaining.

Vettel initially reported that he lost drive but then told his team: "So the rear-left is not tight. The nut is not on, that was the problem."

While Vettel, who ultimately finished sixth quickest, focused on qualifying pace early on, team-mate Kimi Raikkonen worked on race preparation, completing a 20-lap run on the mediums.

The Finn bolted on a set of super-softs later in the session and clocked the fifth fastest time, just two tenths quicker than Vettel's soft lap.

The final third of the session was dedicated to long-run pace, with running split across all three compounds.

Daniil Kvyat was seventh, while Valtteri Bottas, Daniel Ricciardo and Felipe Massa completed the top 10.

Stoffel Vandoorne continued his impressive F1 race weekend debut, as a stand-in for the injured Fernando Alonso, with the 11th quickest time.

The Belgian's time of 1m32.999s was seven tenths off the pace of team-mate Button.

Esteban Gutierrez was the leading Haas in 12th, a couple of tenths quicker than team-mate Romain Grosjean.

Grosjean ran off track late on, reporting that front wing became detached and lodged itself under the car, and that brought out the virtual safety car to clear the debris.

Force India traditionally runs well in Bahrain, but Sergio Perez and Nico Hulkenberg were off the pace in 15th and 17th respectively.

Manor's Pascal Wehrlein was inside three seconds of Rosberg in 19th ahead of the Sauber duo and his team-mate Rio Haryanto.

PRACTICE TWO TIMES