Hamilton fastest in Abu Dhabi practice
Lewis Hamilton landed an early psychological blow ahead of Formula One's Abu Dhabi title showdown by lapping faster than Mercedes teammate Nico Rosberg in both Friday practice sessions.
The Briton, 12 points behind the championship favourite going into the final race, lapped the Yas Marina circuit with a quickest time of one minute 42.869 seconds in the early afternoon, when he also had a harmless spin.
The triple world champion then clocked 1:40.861 in the floodlit evening practice.
Rosberg, who need only finish in the top three on Sunday to be sure of his first championship after being beaten in the last two years by Hamilton, was second in both sessions - 0.374 slower in the first and 0.079 off in the second.
Hamilton reported a strange feeling with the gearbox in the evening session but Mercedes said it was one used only on Fridays and of no significance for the race.
"It's been a great day," Hamilton said.
"Generally very smooth with no real issues...we got a lot of work done both on the short and long runs. I'm really happy with the car and we're in a good position for tomorrow."
Rosberg, who has been on pole at the event for the past two years and won last season's race, said he had made a decent start to the weekend.
"It's always interesting going from hot conditions to cooler ones between the afternoon and evening sessions," Rosberg said.
"Adapting to that and knowing what to expect can be a challenge but our car was working well in both sessions."
The Red Bulls of Dutchman Max Verstappen and Australia's Daniel Ricciardo finished P2 in fourth and fifth respectively with Verstappen 1:41.389 shading Ricciardo 1:41.390 by the barest of margins.
They were separated from the Mercedes pair by Ferrari ace Sebastian Vettel, who went third quickest in practice with a time of 1:41.130, but Vettel had his own problems, pulling his car over with 10 minutes left in the session.
"I think I have a gearbox failure," said the German.
Hamilton, who has to finish in the top three to even have a chance of becoming Britain's first four-times champion, and Rosberg have each won nine races this season.
A collision between the two in the day-to-night race, as happened in Spain in May, would instantly hand the championship to Rosberg, although both have played down the chances of that scenario happening.
"It's going to be a weekend like any other where I'm going to go for the race win and do what it takes to get that," Rosberg told reporters on Thursday.
He added that his driving would be "within the limits of what's acceptable, of course."
Brazilian Felipe Massa, preparing for his 250th and last race, was 10th fastest for Williams while Britain's 2009 world champion Jenson Button, also in his final Grand Prix was 12th on the timesheets for McLaren.
Button's car required a power unit change following a troubled afternoon session.
Toro Rosso's Russian Daniil Kvyat suffered two punctures, with a big spin in the second session.