McLaren driver Jenson Button was the fastest in the first practice at the Abu Dhabi Grand Prix, edging Red Bull's Mark Webber.
The Brit clocked 1 minute, 40.263 seconds on the 5.5-kilometer (3.5-mile) Yas Marina circuit on Friday, making him 0.126 seconds quicker than the Australian Webber.
Button's teammate Lewis Hamilton was third while Formula One champion Sebastian Vettel settled for fourth.
Ferrari drivers Fernando Alonso and Felipe Massa, who finished fifth and sixth respectively, struggled during the session. Each spun at one point and Alonso also twice briefly left the track. Williams driver Rubens Barrichello had his session ruined, when he stalled just minutes after it began and never completed a lap.