Legal diffuser cars struggle in Melbourne
After finishing 16th in the first 90-minute session, Hamilton then ended the second 1.5 seconds faster – but down in 18th.
He at least had his McLaren teammate Heikki Kovalainen for company as the Finn was 17th, perhaps underlining the fact their car really is as bad as feared.
The only two drivers behind Hamilton were Renault's Nelson Piquet and this year's lone rookie Sebastien Buemi in his Toro Rosso.
McLaren had hoped progress had been made in the closing two days of the final test in Jerez last week, but clearly not enough.
Their drivers were 1.5secs down on the star of the day Nico Rosberg, who in pre-season threatened to walk away at the end of the year unless Williams provided him with a race-winning car.
It would appear he has his wish as he topped the timesheets at the end of both sessions, with his best lap timed at one minute 26.053secs.
It did not go unnoticed that six of the top seven places in second practice were occupied by the cars that have been embroiled in the diffuser row this week.
It was not until midnight local time last night that the issue was finally resolved as the stewards presiding over the race threw out a protest which had been launched by Ferrari, Renault and Red Bull.
There is still the threat of an appeal, and those three teams will hope the international panel of judges that sits on these matters ultimately side with them, otherwise they face a struggle. Telegraph.co.uk