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* Raikkonen edges out Vettel before heavens open
* Webber sets fastest time in dry morning session
By John O'Brien
SEPANG, Malaysia, March 22 (Reuters) - Kimi Raikkonen carried the form that propelled him to a season-opening victory to Sepang on Friday after the Finn edged a fascinating first day of practice for the Malaysian Grand Prix in his finely balanced Lotus.
The 2007 Formula One world champion was second to Red Bull's Mark Webber in the bone-dry morning session but forged his way to the top of the timesheets in the afternoon before the heavens opened with 30 minutes remaining of second free practice.
Raikkonen lapped in one minute 36:569 seconds to shade the other Red Bull of Sebastian Vettel by 0.019 seconds, with a resurgent Felipe Massa (1:36.661) clocking the third fastest time of the day in his Ferrari.
Spain's Fernando Alonso was fourth fastest in the other Ferrari, marginally ahead of Webber, who was quicker in the morning, and the second Lotus of Romain Grosjean, indicating a tight three-way tussle looms between the teams that filled the podium places in Melbourne last Sunday.
Raikkonen easily held off Alonso and Vettel at Albert Park after a poor qualifying session but on a track where he won his first Formula One grand prix in 2003, the Finn proved he was more than capable of matching the one-lap speed of his rivals.
The Mercedes duo of Nico Rosberg and Lewis Hamilton were a little off the pace but with team principal Ross Brawn hinting the cars were carrying a heavier fuel load to gauge tyre wear, they are likely to be closer to the leaders in qualifying on Saturday.
The battle for the final two spots in Q3 (the 10-car third qualifying round) appears set to be fought between Force India, who showed their strong Melbourne showing was no fluke, the improving McLarens and Sauber.
The second session was a polar opposite to the first in terms of action on the circuit as the prospect of rain forced all the cars out early in an attempt to set timed laps on a dry surface.
Fitted with the medium tyres after using the hards in the morning, almost everyone set faster times before the first drops of rain sent the cars back to the pits before they could start their race simulations in the final half hour of the day.
A heavy shower gave drivers a chance to test their intermediate and wet tyres in anticipation of similar conditions during the race on Sunday, before a few drivers braved dry tyres in the final 10 minutes but no one improved on their times.
In first free practice, Webber topped the charts with a lap of one minute 36.935, just 0.068 seconds ahead of Raikkonen, who lost 40 minutes of the session as Lotus mechanics changed the Finn's KERS battery following his installation lap.
World champion Vettel clocked 1:37.104, marginally ahead of Alonso, who won this race last year, and Rosberg.
Mindful of the rapid tyre wear experienced with this year's Pirellis, all 22 drivers opted to complete installation laps at the start of the session before returning to the pits and watching the clock tick down to the final hour.
Spectators would have been disappointed to have arrived at the track and not witnessed any action after the early flurry of activity until the cars returned to the circuit to set timed laps on low fuel loads for the second 30 minutes of the session.
"We are trying to find the optimum time to run the cars but we appreciate the concerns of the fans, who want to see cars on the track," Brawn said in a television interview.
"It may be a good idea to have a sacrificial set of tyres for us to use in practice." (Editing by Patrick Johnston)