Ferrari were once more the Silver Arrows’ closest challengers, with Kimi Raikkonen finishing the 90-minute session in third place, albeit almost two seconds down on Rosberg’s leading pace.
Sebastian Vettel meanwhile elected to stick with mediums throughout and was the fastest runner on them, down in 11th place on 1m 35.073s - 2.7s slower than the Silver Arrows.
The Red Bulls again looked good, with Daniel Ricciardo edging team mate Daniil Kvyat by less than one tenth of a second in the fight for fourth. Nico Hulkenberg was within striking distance of them throughout, taking his Force India round in 1m 34.610s for an eventual sixth. Toro Rosso also looked strong again, with Melbourne sparring partners Carlos Sainz and Max Verstappen seventh and eighth, the pair covered by just 0.067s.
Williams’ session was notable for the horrible handling of both FW38s as Felipe Massa and Valtteri Bottas had to try and rotate them around understeering front tyres to get them turned in, and they were both upstaged by Romain Grosjean’s impressive performance for Haas. The Frenchman was ninth on 1m 35.000s, six-thousandths ahead of the Massa.
Down at McLaren the big interest was Stoffel Vandoorne’s official debut. The Belgian, a three-time winner in Bahrain in GP2, made a quiet start to his first weekend in F1 however, winding up 18th.
Jenson Button was four places and one second up the road, but it had looked better early on when the Briton vaulted to third with a soft-shod lap of 1m 35.440s. He didn't improve on that early time though and was gradually shuffled backward as others made gains.
Down at Force India, Alfonso Celis made his Grand Prix weekend debut in place of Sergio Perez; he was 20th on 1m 37.287s.
The other big talking point was another polished run from Pascal Wehrlein in the Manor. On mediums he wound up 15th - fractions ahead of Vandoorne, and a comfortable 1.4s quicker than team mate Rio Haryanto, who propped up the timesheet in 22nd.