Jenson Button set the fastest time in the first free practice session for the Abu Dhabi Grand Prix as McLaren dominated for much of the 90 minutes.
The squad was denied a 1-2 in the final moments, though, when Lewis Hamilton was bumped down to third by Red Bull's Mark Webber. World Champion Sebastian Vettel was fourth fastest ahead of Fernando Alonso and Felipe Massa, despite a problematic session for Ferrari.
Adrian Sutil set an impressive seventh-fastest time for Force India late on, bumping Mercedes driver Nico Rosberg to eighth. Paul di Resta and Jaime Alguersuari completed the top 10, while Friday testers Jean-Eric Vergne (Toro Rosso) and Romain Grosjean (Renault) were 11th and 12th.
Hamilton was out early in the session and set an initial 1m43.899s to bump Renault Friday man and newly crowned GP2 Series champion Grosjean off the top spot after 20 minutes. The two of them, and Daniel Ricciardo, the first men to set times on the Abu Dhabi layout in 2011. Hamilton, on his first long run of the weekend, then set about firing in consistent purple sectors for the next 11 laps until he ended up with a 1m41.846s.
Meanwhile, Williams' Rubens Barrichello was forced to park his car at Turn 13 with a serious technical failure. Having a problem this early on, and having completed only three laps, ensured the Brazilian was locked at the bottom of the times.
It was 35 minutes into the session before things began to heat up as Vettel moved to second in the times, 1.7sec behind the leading McLaren, and a tenth faster than Pastor Maldonado, who was one of the first to try out the option tires.
This triggered a busy period in the session as the dusty track cleaned up and several top runners posted early improvements – none as fast as Hamilton – to establish an early order of Hamilton, Vettel, Webber, Alonso, Button and Maldonado. That didn't last long, as Button found his groove and went just 0.015sec slower than the No. 3 McLaren had done. Then the Red Bulls fired in fast laps instantly pushing Webber and Vettel to the fore, only for Button to respond again with a 1m40.955s. That lap was half a second quicker than the field, and established him at the top of the order.
With 55 minutes gone, Hamilton emerged from the pits for his second, shorter, run and instantly lowered the mark again to a 1m40.466s before heading straight back to his garage. Around the same time, Vettel posted a new improvement to go second fastest, 0.341sec back, splitting the McLarens. While Massa, who had just improved to fifth behind Webber, spun his Ferrari dramatically at Turn 1.
Just after the hour mark, Massa's teammate Alonso had a similar problem at Turn 5, as Heikki Kovalainen also spun his Lotus under the Yas Hotel. The Spaniard would go off the road again 10 minutes later, indicating that all was not well down in the Scuderia's setup department.
The frontrunners began bolting on the development soft tires with 25 minutes to go and Button was the first to move forward, setting a 1m40.263s lap to move ahead of Hamilton at the top of the times. Webber, too, improved, but not enough to get ahead of the two McLarens. The Australian went faster still a couple of laps later – in fact, he set the fastest sector one time of anybody, but still the 1m40.412s he produced was not good enough to move him ahead of Button and Hamilton.
There was the usual flurry of activity late in the session, but Button's time was to stand as only Webber improved significantly. Though this might have been partly due to Vitaly Petrov's late session car failure which left debris on the track and prompted a yellow flag zone in the final sector.
Pos Driver Team Time Laps
1. Jenson Button McLaren-Mercedes 1m40.263s 21
2. Mark Webber Red Bull-Renault 1m40.389s + 0.126 26
3. Lewis Hamilton McLaren-Mercedes 1m40.403s + 0.140 27
4. Sebastian Vettel Red Bull-Renault 1m40.755s + 0.492 27
5. Fernando Alonso Ferrari 1m40.801s + 0.538 25
6. Felipe Massa Ferrari 1m41.260s + 0.997 17
7. Adrian Sutil Force India-Mercedes 1m41.340s + 1.077 23
8. Nico Rosberg Mercedes 1m42.130s + 1.867 26
9. Paul di Resta Force India-Mercedes 1m42.151s + 1.888 28
10. Jaime Alguersuari Toro Rosso-Ferrari 1m42.377s + 2.114 26
11. Jean-Eric Vergne Toro Rosso-Ferrari 1m42.633s + 2.370 26
12. Romain Grosjean Renault 1m42.685s + 2.422 29
13. Vitaly Petrov Renault 1m43.118s + 2.855 13
14. Pastor Maldonado Williams-Cosworth 1m43.255s + 2.992 29
15. Michael Schumacher Mercedes 1m43.389s + 3.126 24
16. Sergio Perez Sauber-Ferrari 1m44.412s + 4.149 28
17. Kamui Kobayashi Sauber-Ferrari 1m44.484s + 4.221 18
18. Heikki Kovalainen Lotus-Renault 1m44.565s + 4.302 27
19. Jarno Trulli Lotus-Renault 1m44.898s + 4.635 25
20. Tonio Liuzzi HRT-Cosworth 1m46.385s + 6.122 28
21. Daniel Ricciardo HRT-Cosworth 1m46.532s + 6.269 27
22. Timo Glock Virgin-Cosworth 1m48.024s + 7.761 20
23. Robert Wickens Virgin-Cosworth 1m48.551s + 8.288 23
24. Rubens Barrichello Williams-Cosworth 3
All Timing Unofficial