Nico Rosberg usurped Mercedes team-mate Lewis Hamilton at the top of the timesheet in a final practice session for the Australian Grand Prix that was littered with issues for many drivers and teams.
Rosberg posted a lap of one minute 29.375secs around Albert Park in Melbourne, bettering Hamilton's time from Friday by three tenths of a second.
That, however, was still 3.4secs slower than the quickest practice lap a year ago, although with the new power unit systems being so raw, there is promise of more pace to come as the potential is unlocked over the course of the year.
The key for now with the 1.6-litre V6 turbo-charged engines that have replaced the 2.4-litre V8s is reliability, and that is proving a hard task to master.
Williams' Valtteri Bottas and Esteban Gutierrez in his Sauber both suffered gearbox issues, forcing the teams into a change and with it an automatic five-place grid penalty.
Given gearboxes this year are meant to last for six grands prix, to change so early will be a major concern.
After a horrific day on Friday for Lotus as they encountered problem after problem, there was no let-up on Saturday.
The Enstone-based marque, along with Marussia, both played one of their five curfew 'jokers' for the season that allows them to work on their cars into the early hours.
Romain Grosjean managed just four untimed laps and at various times voiced his concerns, describing the car as "awful", "horrible", and adding that "nothing is solved" after earlier bemoaning a misfire.
At the end of the hour-long session, team-mate Pastor Maldonado was forced to park his car on the side of the circuit due to a problem, albeit at least after completing 15 laps, but with the Venezuelan down in 18th place, 5.5secs adrift of Rosberg.
Even reigning four-time champion Sebastian Vettel had cause for complaint late on as he also described a different setting on his Red Bull as "horrible", adding that "the car does not accelerate".
Sebastian Vettel finished in 12th position, three seconds behind his German compatriot Rosberg, who was out on his own in front as his nearest challenger was McLaren's Jenson Button, 1.4secs adrift.
Button was followed by the consistent Fernando Alonso in his Ferrari and the second Mercedes of Hamilton, obviously looking at different settings as he was a second down on his best time from Friday.
Force India fared reasonably well with Nico Hulkenberg and Sergio Perez sixth and ninth, sandwiched either side of Kimi Raikkonen in his Ferrari and McLaren rookie Kevin Magnussen.
Further down the field, on a bad morning for Sauber, Adrian Sutil described his car as being "all over the place", and "so bad", with the German almost five seconds down in 15th.
After managing a lap apiece on Friday due to a litany of problems, there was relief in the Caterham garage as Kamui Kobayashi and Marcus Ericsson completed 19 and 21 laps respectively, but with the latter almost seven seconds behind Rosberg.
Marussia's Max Chilton was 17th, 5.4secs back.