Rosberg puts Williams on top in Spain

By Alan Baldwin

BARCELONA (Reuters) - Nico Rosberg led a Williams one-two in practice for the Spanish Grand Prix on Friday after Formula One championship leader Jenson Button had set the early pace.

Rosberg, who has been fastest in eight of the season's 14 practice sessions to date without finishing higher than sixth in a race, clocked the day's quickest time of one minute 21.588 seconds at the Circuit de Catalunya.

Japanese team mate Kazuki Nakajima, who has yet to score a point this year after finishing only one of the four races, was second, 0.152 slower, in an afternoon session that saw Spain's double world champion Fernando Alonso third for Renault.

Rosberg's afternoon was clouded late in the second session however when he stopped with a mechanical problem.

"Today was our first run with the new aero components on the car and they all seemed to work well," said Rosberg. "They're giving us a few tenths extra per lap so we've made definite progress."

Button, chasing his fourth win in five races for Brawn GP, made a dream start in the morning with a best lap of 1:21.799 and was sixth later on. The leading times were all well inside Kimi Raikkonen's 2008 pole position for Ferrari of 1:21.813.

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