The Ferraris of Sebastian Vettel and Kimi Raikkonen were also in the hunt, setting the fourth and fifth fastest times, followed by the Williams of Valtteri Bottas and the Toro Rosso of Max Verstappen. Force India’s Nico Hulkenberg, Toro Rosso’s Carlos Sainz and Lotus’s Pastor Maldonado completed the top ten.
Alexander Rossi had been having an impressive first session as a Marussia race driver, all but matching team mate Will Stevens at the bottom of the order, but the American brought out the red flags near the very end of the 90 minutes when he crashed at Turn 18, causing extensive damage to his car.
The session began amid sweltering temperatures and humidity, but on a dirty track that compounded a lack of grip early on. Rosberg set the pace almost immediately, but Ricciardo quickly showed Red Bull's potential by going faster than Hamilton and after 30 minutes the top five read: Rosberg on 1m 49.184s, Ricciardo on 1m 49.596s, Hamilton on 1m 49.677s, Raikkonen on 1m 49.718s and Vettel on 1m 49.950s, with 0.766s separating them. Hulkenberg and Force India team mate Sergio Perez were up next, with Bottas's Williams, Maldonado's Lotus and Fernando Alonso's McLaren completing the top ten.
Things remained close in the second half hour, with Rosberg still leading - now on 1m 47.995s - as Hamilton improved to second on 1m 48.314s, ahead of Ricciardo on 1m 48.439s, Vettel on 1m 48.494s and Raikkonen on 1m 48.785s. Hulkenberg was sixth as the upgraded Toro Rossos of Sainz and Verstappen moved up, while Maldonado brushed the wall with his right-rear wheel and Alonso stayed in the top 10.
As night fell in the final 30 minutes most of the front runners focused on longer runs, but Vettel understeered off at Turn 5 and was lucky to get his Ferrari stopped before it could make contact with the wall. Bottas and Verstappen, meanwhile, improved, which bumped Alonso out of the top ten. The Spaniard nevertheless had an encouraging session for McLaren on a track where power is less important, though he did have to contend with charging problems which prevented him from improving on his time of 1m 50.123s.
The midfield proved to be incredibly tight - Sainz, Maldonado, Alonso, Perez and Felipe Nasr in the upgraded Sauber were split by little more than 0.1s, while Lotus's Romain Grosjean, McLaren's Jenson Button and Sauber's Marcus Ericsson were fractions of a second further down the road.
Felipe Massa struggled to 17th place in the second Williams, while Daniil Kvyat was restricted to just eight laps and 18th place in the second Red Bull due to fuel system problems.
Down at Marussia, meanwhile, Rossi was initially faster than team mate Will Stevens, with half a second splitting the pair after the first half hour. The Briton subsequently got back ahead by just 0.015s, and with just under four minutes to go the American brought out the red flag after getting a little too much oversteer in the Turn 18 right-hander, hitting the wall and damaging the right-hand suspension of his MR03B.