Sebastian Vettel was half a second behind Hamilton in the Scuderia’s lead car, with team mate Kimi Raikkonen hot on his heels in fourth place. Red Bull, meanwhile, had another strong session, with Daniel Ricciardo edging Williams’ Valtteri Bottas for fifth on the timesheet.
In overcast conditions following rain spots during lunch, Rosberg set the ball rolling with 1m 13.793s on the medium Pirelli tyres but Hamilton replied with 1m 13.634s before Rosberg trimmed down to 1m 13.770s. Vettel was third on 1m 14.469s, then 1m 14.437s.
It was yet another tough afternoon for McLaren. Just after he and Bottas had led the switch from the medium tyre to the soft, Fernando Alonso ran wide and then soon afterwards stopped in Turn 4 with what looked like another Honda powertrain issue. The Spaniard reported a power problem, before sitting disconsolately on the barrier as the MP4-30 was recovered.
Just before that Bottas had used the softer compound to squeak ahead of Hamilton by 0.031s, as the similarly shod Felipe Nasr jumped to fourth for Sauber with 1m 14.134s.
After a nine-minute hiatus Hamilton used the softs to go fastest with 1m 12.843s before Rosberg demolished that with 1m 12.385s. Further back, Vettel managed 1m 13.345s. Then with 35 minutes to run, Rosberg aborted the first of his race runs and came through the pits prior to stopping just on the exit to report a definite problem with the upshifts. He managed to reset the car and continue, but later said he still had problems. At one stage he had a major right front lock-up in Turn 11, before running off the track completely in Turn 12.
By this stage the light rain was making the track slippery. Bottas in particular gyrated off track in Turn 9 and requested a check on rear-wing stability, and everyone settled down to do their race running.
That left Raikkonen fourth for Ferrari on 1m 13.500s despite a clutch problem and a happy Ricciardo next in the Red Bull with the latest-spec Renault power unit in a close fifth on 1m 13.585s ahead of Bottas’s 1m 13.603s.
Completing the top ten were Lotus’s Romain Grosjean, Force India’s Nico Hulkenberg, Red Bull’s Daniil Kvyat and Williams’ Felipe Massa.
Immediately following the session, stewards announced that Bottas is under investigation for allegedly overtaking Nasr under red flags whilst Alonso's stricken car was being recovered.