"We didn't really get into the groove and rhythm", he admitted, "and that's quite important around here".
Alarm bells were ringing when team engineers could be seen taking a hammer to Ricciardo's seat in the garage in a desperate bid to get the belt to fit.
Aussie favourite Daniel Ricciardo announced past year that he was joining Renault for the 2019 season, and he partners Nico Hulkenburg who will hope to prove his pace beside his new teammate.
"I think if there is someone who can drive the charge the top three, that's [Ricciardo]".More news: Pound falls sharply on Brexit deal advice
"The auto is in a similar place to where it was in Barcelona, which is really positive coming from a different track".
I can feel I have the auto under me that I had in testing, but it doesn't do the same thing.
"There's a lake there, there are ovals there and buildings, so we're talking about subtle adjustments that can improve the racing".
Alfa Romeo, formerly Sauber, named Kimi Raikkonen to partner Antonio Giovinazzi in 2019 and the Swiss team are hopeful of being prominent in what will be an enthralling midfield battle.
Vettel slid onto the grass at turn one early in the afternoon run.More news: Nancy Pelosi: President Donald Trump 'not worth' impeaching
The German skidded into trackside grass at one corner and said the auto was still wobbly at turns on another run after taking it back to the garage for work.
Formula 2 Champion, George Russell in the Williams, but also Lando Norris for McLaren, the latter becoming Britain's youngest ever driver in Formula 1 at 19 years old.
A red flag was thrown, despite Albon being able to recover to the pits missing his front wing but with seemingly minor damage to the rest of the vehicle. Mercedes looks very quick. "It's something I've kind of also realised over the past years and especially last year that I definitely only have one career and I don't want to be in the situation that after the season where I should have done this or that".
It was a tricky second session for the inexperienced drivers, with Alexander Albon again making errors after his crash in FP1.
However, Red Bull boss Christian Horner also added a note of caution around Mercedes' single-lap pace, observing: "The auto looks stiff and hard to drive".More news: Senate votes to rebuke president's emergency declaration
FIA chief Jean Todt held a minute's silence to mark his passing in a press conference, with deputy race director Michael Masi fulfilling Whiting's duties in Melbourne.