Returning Raikkonen sets fastest lap in Jerez
His time of one minute 19.670 seconds was quicker than any lap in testing at the track in 2011.
Jerez: Kimi Raikkonen rolled back the years with the fastest lap for Lotus on the first day of Formula One testing on Tuesday.
The 2007 champion, making his comeback after two years in the world rally championship, looked at home right from the start of a chilly morning in southern Spain and completed 73 laps.
His best time of one minute 19.670 seconds was quicker than any lap in testing at the track last year.
That could be explained by a number of technical factors, and any early excitement had to be tempered with the knowledge that the fastest driver in last year's Jerez test was Brazilian Rubens Barrichello, who went on to score just four points for Williams all season.
"It was a positive day. The lap times don't matter today. I'm happy with the balance of the car, which feels good, and the fact that we didn't have any major issues," said Raikkonen.
"Also, I did more than a race distance today and did not have any physical problems at all, which is good."
If Raikkonen was his familiar self afterwards, facing a media scrum outside the former Renault team's motorhome with deadpan replies and barely a flicker of emotion beneath his oversize cap, Finnish reporters were thrilled.
As one explained, a happy 'Iceman' walked with a spring in his step whereas when things were going less well Raikkonen showed all the verve of a snowman. On Tuesday there was a definite bounce.
Britain's Paul di Resta was second fastest for Force India ahead of Germany's Nico Rosberg in last year's Mercedes and Australian Mark Webber in the new Red Bull.
The session was twice red-flagged, first when Australian Daniel Ricciardo stopped his Toro Rosso on the track with an oil pressure problem and then when Sauber's Kamui Kobayashi ran out of fuel.
Webber had to wait to get out on track with the title-winning team's plans hampered by a plane carrying the RB8's rear wing assembly being diverted from Jerez to Seville due to early morning fog.
"Sometimes we can't control Mother Nature so we risked it a bit tight on the schedule and we paid a bit of a price, which can happen sometimes," said Webber, winner of the final race of 2011 in Brazil.
"There are obviously lots of changes. Aerodynamically, the concept is a bit different because of the regulations, but we are satisfied," he added.
With an array of new cars on track for the first time, the McLaren stood out as the only car other than the Mercedes and ageing HRT not to have the new stepped nose that all have adopted to satisfy the revised aerodynamic and safety rules.
Britain's Jenson Button, the 2009 champion, appeared happy enough with his day in a marked change from last year when McLaren started testing with a car that was soon shown to be hard to handle and way off the pace.
"There are no niggly areas with the car, which is nice. Quite different to last year. I'm happy," the 2009 champion told reporters.
"The front wheels are on the front, the rear wheels are on the back, it feels like it's going in the right direction, and when you turn right, it goes right. Sometimes that hasn't been the case."
He gave Raikkonen a reminder of what he can expect this season, when there will be six champions on the starting grid, by overtaking him on track near the end of the session.
"He's obviously in a very competitive car, and whatever they did today - low fuel or whatever - it was still quick. So fair play they've had a good day," he said of the former McLaren driver.