Lewis Hamilton and Jenson Button head Abu Dhabi practice
The McLarens of Lewis Hamilton and Jenson Button set the pace as rivals Sebastian Vettel and Fernando Alonso crashed out in Abu Dhabi.
Hamilton led Button by 0.199 seconds as the sun set on practice for Formula 1's only twilight race.
Vettel returned to the track despite flicking his Red Bull into the barriers at Turn One and was sixth fastest behind team-mate Mark Webber.
Alonso's Ferrari went off at the same part of the track but was still third.
Vettel is the only man to win at Abu Dhabi's stunning Yas Marina circuit - where he beat Alonso, Webber and Hamilton to the 2010 world title.
“I lost the car at the entrance. I think I was a little bit too wide, a little too much on the kerb and then lost the rear”
But the double world champion provided a heart-in-the-mouth moment of another kind when he lost control at the end of the main straight going into Turn One with 35 minutes to go in the evening session.
His Red Bull snapped into a half spin and slid across the track, wedging into the barriers.
Vettel climbed out and stood with a gloomy expression on the sidelines, anxious to get back in the car - which he eventually did.
"I lost the car at the entrance," Vettel said. "I think I was a little bit too wide, a little too much on the kerb and then lost the rear.
"I couldn't catch the car any more and was quite lucky to get out again at the end so there wasn't any damage apart from the front wing. We'll see what we can do now.
"I think we are there and thereabouts. The gap was a bit too big but it's difficult to judge what other people do."
Shortly after Vettel's crash, Alonso found himself in the wall at the same spot to cap a troublesome day for Ferrari.
“We need to be very careful in Turn One when we arrive in final qualifying and be calm on that braking”
"For the crash, I think I braked on the outside of the corner," Alonso said.
"There is a kerb on the outside and looking at the videos all of us that had incidents there braked on the outside kerb.
"We tried to maximise the track in all the corners but we need to be very careful in Turn One when we arrive in final qualifying and be calm on that braking."
McLaren were the only leading team to have a problem-free day and even before taking to the track they had been optimistic that they could overhaul Red Bull in the fight to the chequered flag this weekend.
Hamilton said in Abu Dhabi that two wins in the final pair of races would make a "big difference" to his rollercoaster season and he made a positive start by setting the benchmark on Friday with signs of a promising race pace during his longer stints on track.
Despite his positive mood in Abu Dhabi, Hamilton still managed to grab the headlines by dismissing as "rubbish" McLaren team principal Martin Whitmarsh's suggestion that he was feeling pressurised by Button's success .
Button has three races victories compared to Hamilton's two but the English team-mates took it in turns to lead the timesheets in Abu Dhabi.
Button led the way in the first session in the afternoon before Hamilton set a benchmark of one minute 39.586secs as the moon rose over the stunning Yas Marina circuit.
“The car looks very good, Lewis looks very fast so it shows the car is very quick”
"It was a great day for us," Hamilton said. "The car looked pretty good and the long-run pace doesn't feel bad. I'm happy.
"The track was clean from quite early on and it got better and better. I don't understand why the others were having problems but it's only practice."
Button added: "I'm still not entirely happy with the balance and I haven't been all day.
"We're going in the right direction but there are still areas that we're lacking.
"The car looks very good, Lewis looks very fast so it shows the car is very quick. The long run that I did was all right but I still think there's room for improvement."
In contrast, the Ferraris looked a bit of a handful for Alonso and Massa, who endured a series of spins and off-track moments before Alonso lost his car altogether in the evening session.
"Ferrari have been jumpy this weekend," said BBC pit-lane reporter Ted Kravitz, who suggested that the team had struggled with their brakes and even the wind direction.
They are also continuing for the third race weekend in a row their tests of a new front wing which they are developing for use on their 2012 car.
But Alonso still managed to stay in touch with the McLarens, finishing the day just 0.385secs behind Hamilton's time.
Mercedes driver Michael Schumacher was less than a second off the pace as he set the seventh fastest time ahead of the Force Indias of Adrian Sutil and Paul di Resta.
There were several drivers who were out to prove their worth in the final two races of the season here in Abu Dhabi and then in Brazil.
Frenchman Jean-Eric Vergne, who will drive the championship-winning Red Bull in next week's young driver tests at this track, was just 0.256secs behind Toro Rosso's regular driver Jaime Alguersuari in the first session.
Swiss Romain Grosjean also returned for Renault, for whom he drove in the second half ot the 2009 season before stepping back into the GP2 feeder category, which he won this year.
The 25-year-old finished 12th and nearly half a second ahead of Petrov but cautioned: "It was a better help for next year but it doesn't mean either that I'm going to be in the car."
Canadian Robert Wickens declared himself happy after finishing within half a second of Virgin stalwart Timo Glock in his first run in practice.