New Lotus signing Kimi Raikkonen completed a headline-grabbing return to F1 action at Jerez by ending the first day of winter testing at the top of the timesheets.
The 2007 world champion, making a comeback to the sport this season after a two-year spell in the World Rally Championship, topped the 12-driver field with a best time around the twisty Spanish test circuit of 1:19.670 set mid-way through the morning's running, which was enough to edge out Force India's Paul di Resta by a tenth of a second.
Nico Rosberg was third in the 2011 Mercedes - the Brackley-based outfit opting to complete more work on their new car rather than press it into service for the first test - with Mark Webber fourth in the new Red Bull RB8.
The double World Champions' start to pre-season had been slightly delayed in the morning by the late arrival of some car parts following earlier heavy fog in the area. But once on track just before midday local time, Webber steadily worked his way down into the mid 1m20s by the end of the day having put 54 laps on the car everyone has to beat in 2012.
It was a relatively low-key start for Red Bull's two chief rivals, McLaren and Ferrari, who, for what it's worth given it was only the first day of pre-season, finished over one and a half seconds adrift of the pace set by Raikkonen.
Jenson Button, the 2011 championship runner-up, kicked off McLaren's programme in the MP4-27 - which uniquely continues not to feature the 'stepped' nose seen on all other 2012 cars launched so far. The Briton completed 62 laps to finish eighth on the times, one spot higher than Felipe Massa.
"It's been a good day: this morning, we ran through our installation and systems checks and the running was good," Button said. "We've been gathering data on aerodynamics, downforce levels, temperatures and the feeling inside the cockpit.
"We did a 15-lap timed run this afternoon, which is a good starting point for us - and the consistency was okay. It's been a positive day: there are no niggly areas with the car, which is nice. Overall, today was just a starting point, and was all about putting miles on the car. There are some promising signs, so I'm happy."
Ferrari said Massa, whose F2012 was initially painted with flow-vis paint across its rear wing for the team to complete some early aerodynamic evaluations, concentrated on - as is normal for the first test with a new car - data collection during the course of his 69 laps on track.