Whilst the opening week of testing might have led new boys Haas to think that this F1 lark isn't quite as difficult as it looks, leading to the obligatory 'targeting points in Melbourne' headlines, it has been a return to planet earth with a bump this week.

Following yesterday's fuel system issue which resulted in Romain Grosjean only completing 23 laps, today, a turbocharge problems has side-lined teammate Esteban Gutierrez, the Mexican only completing an installation lap at the very start of the session.

An hour before the break, Guenther Steiner revealed that "after changing the turbo charger last night we saw an anomaly, we’re investigating and we hope to be back out later".

Another driver who missed much of this morning's running was Marcus Ericsson. Following a successful debut yesterday, the Sauber C35 didn't appear until the final moments of this morning's session, Ericsson managing to post a 30.309 before the break.

At the other end of the timesheets, the leaders are clearly already looking ahead to Melbourne and beyond.

Lewis Hamilton spent much of the morning on longer runs, which he permeated with simulated starts and grid waits. Finally, bolting on a set of the softs, he went for a time, eventually taking top spot with a 23.622.

Sebastian Vettel, who initially set the pace, then switched focus to longer runs, shunning the soft rubber for medium.

Daniel Ricciardo was among the last to post a time, the Australian initially completing no less than 13 laps, pitting at the end of each for a practice pit stop.

Another driver to try the softs was Jenson Button, the Briton as high as third at one point before dropping to fifth. With 45 laps under its belt McLaren must be feeling a lot more confident than it did a few days ago, though a suspension issue is understood to have caused some concern just before lunch.

The only driver to try the supersoft rubber was Kevin Magnussen who briefly topped the timesheets before being put in his lace by Hamilton. Nonetheless, a positive morning for Renault.

Bottas was the first driver to go hard, the Finn subsequently switching back to mediums and posting a 25.151.

Toro Rosso and Force India are quietly getting on with the job, concentrating on reliability rather than pace, whilst Pascal Wehrlein has put another 43 laps on the Manor as the Banbury team continues its softly, softly approach.

Check out our Wednesday gallery, here.