Nico Rosberg and Mercedes maintained their place at the top of the timings following second practice in Australia.
The first use of the soft compound Pirelli tyres saw the lap times drop nearly two seconds from the first session as the German posted a 1:27.697, a full tenth clear of team-mate Lewis Hamilton who again had to settle for P2.
The big improvers in the afternoon were Ferrari as Sebastian Vettel closed to within three-quarters of a second of the Silver Arrows in third and Kimi Raikkonen also highlighting Ferrari's progress in fourth.
Williams & Red Bull hit trouble
In the battle to be best-of-the-rest behind Mercedes, the expected main contenders to Ferrari had to rely on a sole driver to complete the donkey work on Friday.
Daniel Ricciardo for Red Bull and Felipe Massa at Williams both failed to exit the pits as a failure in the internal combustion engine meant a full power unit change for Ricciardo while a water leak was the cause of Massa's troubles.
Their respective team-mates did do the jobs required, however, and, while Valtteri Bottas was a little further behind the Ferrari's than most expected, both he and Daniil Kvyat claimed fifth and sixth respectively on the timings.
With the gains made by Ferrari and the already established dominance of Mercedes, Red Bull are unsurprisingly struggling to match their rivals over a single lap with eight tenths separating the Russian Kvyat to the Finn at Williams.
McLaren's mountain realised
It would have been ridiculous to have expected McLaren-Honda to have reformed their iconic partnership and be competitive from the get-go but the scale of their task to achieve the goals they have set is finally becoming clearer.
Hindered by a crash for Kevin Magnussen, who lost the rear and hit the barrier on the exit of turn six, there was some progress in the second session though Jenson Button having to curtail his race simulation a little early due to a loss of power meant their late afternoon wasn't trouble free.
The 2009 champion completed 21 laps in the 90 minutes with a best of 1:31.387 nearly four seconds slower than Mercedes and ultimately putting them in the likely position of being the slowest team on the grid with the exception of Manor.
It does appear the problem is purely engine related as Button claimed the Force India of Nico Hulkenberg was struggling to keep up through the corners and we also saw Daniil Kvyat pull an easy overtake on the Briton along the straight to turn 13.
Lotus and Toro Rosso lead midfield
After each team got at least one car into the top 10 in the first practice, it was Lotus who managed to get both into what would be points scoring positions in the second session.
A battery problem caused Max Verstappen to lose out on track time in the afternoon but his team-mate Carlos Sainz Jr. was seventh with the two Mercedes-powered E23's eighth and ninth as Pastor Maldonado led Romain Grosjean.
Nico Hulkenberg had a troubled session sorting out a vibration on his Force India but seemed to have found a solution by the chequered flag and completed the top 10.
Long runs offer few changes
As is accustom in the second session, the final half an hour was handed over to longer runs as teams looked at fuel consumption and tyre degradation.
Much like over a single lap Mercedes continue to set the pace with a few tenths advantage per lap over the the rest of the field. Interestingly, between the two drivers it remained Rosberg who had the slight edge over Hamilton but whether it plays out to that theme over the rest of the weekend remains to be seen.
Behind, Ferrari, particularly Kimi Raikkonen, looked strong and the Finn was setting fast times through to the end of the session.
Bottas too was stronger on the longer run but Kvyat continued to suggest Red Bull are lagging behind in fourth on the pecking order. Indeed Lotus even looked a possible threat to the young Russian but following Ricciardo's pace in the final session on Saturday may give a better indication as to where the RB11 actually stands.
The durability of the tyres was hard to gauge, a two-stop strategy looks the most likely across the board but some may opt for a three.
A two-horse race?
Whatever the strategy, however, it looks like reliability is the only thing standing between Mercedes and a first one-two finish of the season. The new W06 is holding an advantage most had expected following the best times in testing but all the answers will finally be revealed when they go peddle-to-the-metal in qualifying on Saturday.
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