Kimi Raikkonen was Ferrari’s leading runner in P4, but was also nearly two seconds back of the Silver Arrows having run on the same tyres.
Under clear blue skies, Hamilton and Rosberg opted to run supersofts early on when the track was still very dusty, the Briton going fastest on 1m 39.246s to the German’s initial 1m 40.223s. Subsequently they trimmed those times down to 1m 38.943s and 1m 39.421s respectively, then 1m 38.701s and 1m 39.038s.
At that stage Raikkonen and Vettel had been their closest pursuers, on the soft tyres, the Finn posting 1m 42.738s to go fastest early on. Raikkonen then improved to 1m 41.110s before Vettel did 1m 39.988s.
Conditions were improving however, and eventually both Mercedes drivers set their fastest times on the soft tyres, Hamilton lapping in 1m 37.428s to head Rosberg by 0.315s.
Max Verstappen started out doing data acquisition with his Red Bull RB12, but later used the mediums to lap in 1m 39.379s and move ahead of Raikkonen. Nico Hulkenberg had a strong day for Force India with 1m 39.71s on the supersofts to take fifth place as Valtteri Bottas used softs to put Williams sixth on 1m 39.776s. Daniel Ricciardo was seventh in the second Red Bull with 1m 39.963s, also on mediums, as Vettel’s 1m 39.988s held up for eighth.
The German had a problem in the second part of the session when debris, which may have come from his own front wing, damaged the right-hand mirror, obliging him to drive one-handed back to the pits as he held on to the broken component. The Virtual Safety Car was briefly deployed while debris was cleared away.
The top ten was completed by the Toro Rossos of Daniil Kvyat - who along with Renault's Jolyon Palmer spun at Turn 18 during the session - and Carlos Sainz. Felipe Massa was on their tails with the other Williams, on 1m 40.191s.
In Haas's home race, Romain Grosjean and Esteban Gutierrez were 14th and 15th - and there was minor embarrassment for the team at the end of the session when the Mexican stalled at the pit lane exit, and the Frenchman’s engine also stopped; both cars had to be wheeled back to their pits.
Alfonso Celis Junior did a decent job for Force India, taking Sergio Perez’s car to 1m 41.422s for 17th, and Jordan King’s first F1 race-meeting outing in Pascal Wehrlein’s Manor left him an impressive 20th on 1m 42.012s - two spots and 1.8s up on stable mate Esteban Ocon.