By Alan Baldwin
SHANGHAI (Reuters) - Last year's winner Nico Rosberg led Lewis Hamilton in a Mercedes one-two at the top of the timesheets after first free practice for the Chinese Grand Prix on Friday.
The German, who has led the race in Shanghai in the past three editions and whose 2012 win at the monumental circuit was the first of his Formula One career, clocked a quickest lap of one minute 36.717 seconds.
Hamilton, the 2008 world champion who canceled his media engagements on Thursday because he felt unwell, was 0.454 slower.
The Briton, third in Malaysia last month after Rosberg was ordered not to overtake because of concerns the cars might run out of fuel, is the only driver to have won twice in China.
Red Bull's Mark Webber, whose working relationship with world champion Sebastian Vettel hit a new low after a team orders storm in Malaysia, ended the session third and ahead of the German.
Vettel was fourth, 1.225 off Rosberg's pace, while Ferrari's Fernando Alonso lapped fifth fastest and McLaren's Jenson Button was sixth.
Triple champion Vettel leads the championship after two races with 40 points, nine clear of Lotus's Kimi Raikkonen.
China's Ma Qing Hua, in the Caterham that will be raced by Frenchman Charles Pic on Sunday, wrote a footnote in Formula One history by becoming the first Chinese driver to take part in a grand prix weekend on Chinese soil.
He was last of the 22 drivers on track, 6.828 seconds slower than Rosberg, with both Caterhams lagging rivals Marussia at the tail end.
Button's Mexican team mate Sergio Perez damaged the front wing of his McLaren when he skidded off into the gravel at the pitlane entry at the end of the session.
(Editing by John O'Brien)