Lewis Hamilton established himself as the man to beat heading into the Malaysia GP weekend as he topped second practice at the Sepang International Circuit after team-mate Nico Rosberg was fastest in FP1.
Rosberg wound up half a second quicker than his team-mate and title rival in the opening practice session, though he did his set his fastest time on the soft compound tyre, with Hamilton on the slower medium rubber.
It was a dominant start for the Silver Arrows, their tenth 1-2 in the last 11 FP1 sessions, as Kimi Raikkonen and Sebastian Vettel, who took third and fourth respectively, failed to get within a second of the German's benchmark.
The session, though, was overshadowed by a fire on Kevin Magnussen's Renault as the RS16 burst into flames in the pitlane and the Dane was forced to leap from the cockpit, thankfully emerging unscathed.
Fernando Alonso was an encouraging fifth fastest with an upgraded Honda power unit, yet the Spaniard will be forced to start from the back of the grid after installing the new components, which are expected to be fully introduced at the next race in Suzuka.
Daniel Ricciardo and Max Verstappen were sixth and seventh for Red Bull ahead of Force India duo Nico Hulkenberg and Sergio Perez, while Jenson Button completed the top ten.
Mercedes were on top once again in FP2, but this time it was Hamilton who ruled the roost, setting the fastest time in all three sectors en route to a 1:34.944, which saw him finish two tenths clear of Rosberg.
Vettel, the 2015 winner in Sepang, was able to reduce their advantage over the rest of the field to six tenths, but Raikkonen remained around a second off the pace.
The Scuderia, though, looked much stronger relative to Mercedes on the race simulations, and the forecast rain could well threaten the Brackley outfit's dominance.
Verstappen was fifth ahead of Perez, while Alonso completed a promising Friday by taking seventh, out-pacing Ricciardo, Hulkenberg and team-mate Button.
Carlos Sainz was 11th, with Jolyon Palmer a solid 12th, while Williams endured a difficult afternoon as Valtteri Bottas and Felipe Massa managed only 13th and 15th, the Haas of Esteban Gutierrez sandwiched between them. Traditionally, though, the Grove outfit do improve as the weekend progresses.
Daniil Kvyat was nearly half a second slower than his opposite number in 16th as Marcus Ericsson and Felipe Nasr took 17th and 18th ahead of the aforementioned Magnussen, who enjoyed a comparatively trouble-free afternoon in P19.
Romain Grosjean's perennial balance struggles showed no signs of abating as he was forced to settle for 20th, while Manor pair Pascal Wehrlein and Esteban Ocon propped up the order, only a tenth behind the beleaguered Haas driver.