Formula One leader Sebastian Vettel headed off Lewis Hamilton to be fastest in the second practice for the Abu Dhabi Grand Prix on Friday.
Vettel clocked 1 minute, 41.751 seconds for Red Bull on the 5.6-kilometer (3.5-mile) Yas Marina circuit, .168 seconds quicker than Hamilton, who topped the first practice times.
Hamilton's McLaren teammate Jenson Button was third followed by Vettel's teammate Mark Webber.
Vettel's strongest challenger Fernando Alonso of Ferrari struggled to keep pace. He managed to finish only seventh fastest, .836 slower than Vettel. He also lost time when he went off the track.
The other remaining challenger, Kimi Raikkonen of Lotus, was sixth.
The practice in dry conditions was largely without incident though several drivers briefly left the track and two spun out. Among them was Vitaly Petrov of Caterham.
Vettel has won the past four races to overtake Alonso at the top, and by all accounts has the fastest car on the circuit.
Alonso, for his part, has admitted that Ferrari must be faster this weekend to give him any chance of winning his third title. He lamented the fact he finished 10 seconds behind Vettel at the Indian Grand Prix last weekend.
Vettel cannot win the title this weekend but another victory and a strong performance at the United States Grand Prix would make it difficult for anyone to topple him.
Vettel has had mixed results in Abu Dhabi. He won his first championship in 2010 when he won the race to pip Alonso for the title, but last year he crashed out on the opening lap with a puncture. He secured a milestone pole position a day earlier, tying Nigel Mansell's record of 14 in a season.
Hamilton, who won last year's race in Abu Dhabi, was a favorite for the drivers' title after winning the Italian GP on Sept. 9. But he has struggled ever since, failing to reach the podium in the past four races including the Singapore GP where he retired after leading for almost half the race.
Critics have contended his poor performance might be due to the distraction of his much-publicized announcement that he's switching to Mercedes next year.