Mercedes swept the day in Sepang.
Nico Rosberg ended Friday’s on track action at Sepang on top of the charts, with a lap of one minute, 39.909, narrowly ahead of Ferrari’s Kimi Raikkonen and Sebastian Vettel.
Hamilton winded up on top in the first session at Malaysia, giving Mercedes a sweep of the days action on track.
“It was a decent day, tough conditions out there,” said Rosberg.
“It’s very hot, tough for the engine. There is massive tyre degradation out there.”
With much talk about the lightened fuel load on the cars, Rosberg said with the tyres wearing at a very high rate this weekend under hot temperatures, he will be focusing on the rubber.
“Fuel management is not a problem this year not at this track, I am focusing mainly on the tires,” Rosberg said.
Team mate Hamilton echoed Rosberg’s comments about fuel management not being a problem at the track, but did say he cannot push as hard as he wants. Hamilton also added the tires will make tomorrow’s qualifying session, and Sunday’s race very interesting.
“It's too hot for the tires, they are not working very well in these conditions,” Hamilton said.
With the Mercedes drivers taking the top of both sessions, Rosberg said competition between team mates will always be close.
“It will always be close, I just need to try and stay ahead,” the German said.
Daniel Ricciardo ended the second session 7th overall, said that he is happy the cars reliability isn’t in question yet this weekend.
“Pretty pleased with the progress we made,” said Ricciardo. “Reliability was good today, so we are pretty pleased with that.”
Raikkonen’s team mate Fernando Alongso ended in 5th, with Lewis Hamilton taking the fourth spot.
The Lotus Renault team continued to struggle, with Pastor Maldonado not turning a lap, while Romain Grosjean was able to turn 14 laps before a gearbox failed on the car, causing him to stop on track.