Hamilton leading the way in first practice at Sepang

SEPANG, Malaysia, March 23, 2012 (AFP) - Britain's Lewis Hamilton set the pace in opening free practice for the Malaysian Grand Prix Friday as Mercedes also showed blistering speed aided by their controversial new rear wing.

McLaren driver Hamilton, the 2008 world champion, set the quickest time of 1min 38.021sec in the 90-minute session, held in scorching heat at the Sepang circuit, half a second ahead of reigning title-holder Sebastian Vettel.

Mercedes' Nico Rosberg and Michael Schumacher held the third and fourth positions, in a performance which will bring more attention to their new drag-reduction device despite its all-clear by Formula One officials.

Lotus driver Romain Grosjean placed fifth ahead of Vettel's Red Bull team-mate Mark Webber, while McLaren's Jenson Button, who won last week's season-opener in Australia, was ninth.

Despite concerns from rival teams, officials have raised no objections to Mercedes' "W-duct" rear wing which cleverly channels air-flow to cut resistance on the nose when the Drag Reduction System (DRS) overtaking aid is engaged.