The Spaniard set the fastest time of the day in the second session after Italian Vitantonio Liuzzi led the way for newcomers Red Bull in the first.
De la Rosa, who will not race on Sunday, lapped in one minute 25.376 seconds with Finnish team mate Kimi Raikkonen second quickest in 1:25.676 to continue the Mercedes-powered team's strong form in pre-season testing.
"On one of my laps during a long run in the second session one of the Jordans and me touched and I ended up in the gravel," said the Spaniard.
"But there was no damage so I was able to carry on."
Raikkonen and team mate Juan Pablo Montoya limited their running, as did most race drivers, to save engines that must now last for two race weekends.
The Finn did just one lap in the first session after deciding to change gear ratios.
Liuzzi, last year's Formula 3000 champion who could replace Austrian Christian Klien as a race driver later in the year, did his reputation no harm.
He was the only driver in the first session to lap below one minute 26 seconds, despite dirty track conditions.
Ferrari's seven times world champion Michael Schumacher did not complete a timed lap in the morning, when he had a small electrical problem, but finished the afternoon fourth fastest with 15 circuits under his belt.
"Ideally we'd be doing 20-lap runs to make a judgement on the tyres but that's not possible now with the new engine rules," said technical director Ross Brawn.
"We've had to economise a little on the engine mileage but we've done enough to make a judgement that we'll be happy with," added the Briton. "So far we're quite pleased with the work we've done and the position we're in."
Minardi did not take part in either session and resorted to legal action after their car was ruled out for not conforming to the new regulations.
Canadian former world champion Jacques Villeneuve, who took pole position in the first race at Albert Park 10 years ago, was first out on track in his Sauber.
Narain Karthikeyan made his debut as India's first Formula One driver but his track time was cut short in the first session due to a small oil leak.
"I lost a lot of time this morning...so after that I have been pushing very hard," he said. "Now I just need to calm down a bit because I was under pressure to perform."
More from rediff