Rosberg’s fastest time of the afternoon – 1 minute 32.250 seconds – was just 0.072 seconds quicker than Hamilton’s best.
The German hinted after the race that there might be more pace to come from Mercedes.
“It’s been a case of finding my way today,” he said. “On the soft tyre we showed good one-lap pace, the balance felt good, and the track was really exciting to drive.
“It looks like we’re ahead of the Ferraris, but it remains to be seen as to where we are compared to the Red Bulls.”
Hamilton, given the engine fire that deprived him of 25 points at the last race in Malaysia, had one thing on his mind during practice.
“It’s been a really good day with no problems on the car, which is great.” He said. “Hopefully we’ll be going into Sunday in good shape.”
Though it was smooth sailing at the front, Mercedes commanded a smaller gap than expected by the end of the day.
Kimi Räikkönen dragged his Ferrari up the time sheets to just 0.323 seconds behind Rosberg.
“Today I guess the feeling was not very easy but the lap time was okay,” he said. “The balance is not probably where I want it to be.
“If it improves and if we can get the feeling and the car working as we want, we can improve a lot, so we’ll see what happens tomorrow.”
Max Verstappen split Räikkönen from his teammate, but he was almost half a second slower, with the German a further 0.042 seconds back.
Red Bull Racing was able to take solace in Verstappen’s long-run pace, however.
As was the case in Malaysia, the RB12’s tyre usage appeared favourable over a number of laps compared to the Mercedes and Ferrari cars.
“I think actually on both tyres, even on the hard, we looked very good,” said the Dutchman, before cautiously adding “but we have to wait and see if [Mercedes] in the right engine modes.”
Separating Verstappen from Malaysian Grand Prix-winning teammate Daniel Ricciardo were seven cars, including Vettel, both Force India and Williams drivers, and one driver each from McLaren and Toro Rosso.
Ricciardo, however, had an alibi – a virtual safety car triggered by Esteban Gutierrez’s stopped Haas car interrupted his only qualifying simulation run.
With the performance edge scrubbed from his tyres, Red Bull Racing decided to switch him straight onto his race simulation, and his pace for the afternoon suggested he will be well prepared for the race.
“It was a pretty good day,” he said. “I think the lap we had to abort was definitely in the [1 minute] 32s, so it probably would have put me just behind Kimi’s time.
“I think tomorrow we can squeeze a bit more out of it, but we’ll definitely have a challenge.”
The weather radar suggests rain and possible thunderstorms are on the way for qualifying and potentially the race, but Ricciardo feels his chances of repeating his Sepang success would be only heightened in the wet.
“We’re normally good in the wet,” he said. “It might help us get a front row.
“We’ll see, but I’m ready if it is wet. I do like this place, it’s fun in both conditions, so we’ll do what we can.”
Don’t forget to tune in to Live98.5 each and every Saturday from 9am for the Box of Neutrals show.