Williams spent all of yesterday focusing on heavy-fuel longer runs.
But the picture seems a bit different already this morning with Lance Stroll posting a 1:22.7 to top the times at the moment, significantly quicker than the FW40 went when fat with fuel yesterday.
Hulk swaps the numbers in his lap time round next time by and sets a 1m23.345s.
Alonso goes fourth, setting a 1m23.080s on the purple-marked Pirellis.
Quickest personal best times of the morning also swiftly posted by Renault's Nico Hulkenberg and Force India's Sergio Perez, although they're back in the 1:23s.
Certainly a slower start to today's action on the timesheet than recent mornings...but it's still early yet!
1 Raikkonen Ferrari 1m22.704s
2 Stroll Williams 1m22.764s
3 Bottas Mercedes 1m22.809
4 Alonso McLaren 1m23.080s
5 Hulkenberg Renault 1m23.345s
6 Perez Force India 1m23.773s
7 Ericsson Sauber 1m26.384s
Alonso backed off and is now pushing again.
He sets a personal best in the first and second sectors, and then the quickest final sector so far to jump to second on a 1m22.731s.
Stroll can't keep it up over the lap and in the end it's a mid-1m22s.
Ericsson, though, uses unmarked medium tyres to post his best time so far – 1m25.824s.
Our first pitlane update of the day from Sky Sports News HQ's Rachel Brookes with analysis of the situation at Red Bull and with Renault's engine:
"We were told yesterday that the Renault teams have been told they will get a new engine for Australia.
"But there are definitely some niggles in that unit at the moment which could affect Red Bull this season. They haven't put in a really quick qualifying simulation or performance run yet, we're waiting to see what they have.
"The long run yesterday wasn't quite as good as Mercedes and Ferrari and both drivers have said they may not start the season up there with those two teams, but they think they will get there fairly quickly.
"But at the moment it's Ferrari and Mercedes battling for the headlines here, with both saying the other is ahead."
Perez joins Stroll and Ericsson on track. The Mexican's last lap was a 9m46.214s, which is completely unacceptable and will not be good enough when we go racing.
However, after that near-10-minute 'lap' – he was in the pits for a while in case the sarcasm's isn't translating very well on the internets – Perez improves to a 1m23.319s. Much faster.
Ericsson improves to a 1m25.550s, Perez to a 1m22.970s. Both are on mediums.