Button fastest in final Abu Dhabi practice

The pair of British world champions had been closely-matched during Friday's sessions and resumed battle today, with Button sneaking ahead right at the end of the hour and earning his first fastest time in an official session since he took pole in Monaco five months ago.

McLaren driver Hamilton had been the man to beat for the majority of the session.

Toro Rosso's Sebastien Buemi had swapped first place with Hamilton's team-mate Heikki Kovalainen early on, and then Button edged ahead of them with a very early soft tyre run. But then Hamilton completely blew them away with a 1m41.270s lap - 1.1s quicker than anyone else - on hard tyres just before the halfway point.

He later shaved a further 0.2s off that mark, and although Buemi briefly nosed back ahead, when Hamilton switched to soft tyres he rapidly moved back in front with a 1m40.810s two minutes from the end.

That looked set to stand as the best time of the session, until Button - back on harder tyres - stole the top spot with a 1m40.625s. Hamilton, still on his now-worn softs, improving to just 0.002s behind, but Button was going faster still on his next lap before backing off and returning to the pits.

Rubens Barrichello jumped to third in the dying seconds in the second Brawn, ahead of Buemi.

Nick Heidfeld completed the top five for BMW, despite earlier expressing his amazement at team-mate Robert Kubica's pace. In the end, the Pole was three places further back, behind Kovalainen and Toyota's Jarno Trulli. Adrian Sutil and Kimi Raikkonen filled the final top ten places for Force India and Ferrari.

The session passed without major incident, bar a brush of the barrier by Force India's Tonio Liuzzi and two quick spins from Renault's Romain Grosjean.

But while there were no accidents, Jaime Alguersuari was sidelined for the entire hour as his Toro Rosso team worked to fix a hydraulic problem.

Pos  Driver        Team                      Time              Laps
 1.  Button        Brawn GP-Mercedes    (B)  1:40.625           21
 2.  Hamilton      McLaren-Mercedes     (B)  1:40.627 + 0.002   18
 3.  Barrichello   Brawn GP-Mercedes    (B)  1:40.907 + 0.282   20
 4.  Buemi         Toro Rosso-Ferrari   (B)  1:40.934 + 0.309   22
 5.  Heidfeld      BMW Sauber           (B)  1:41.241 + 0.616   18
 6.  Kovalainen    McLaren-Mercedes     (B)  1:41.263 + 0.638   20
 7.  Trulli        Toyota               (B)  1:41.310 + 0.685   23
 8.  Kubica        BMW Sauber           (B)  1:41.322 + 0.697   20
 9.  Sutil         Force India-Mercedes (B)  1:41.372 + 0.747   22
10.  Raikkonen     Ferrari              (B)  1:41.373 + 0.748   23
11.  Vettel        Red Bull-Renault     (B)  1:41.403 + 0.778   19
12.  Rosberg       Williams-Toyota      (B)  1:41.478 + 0.853   22
13.  Kobayashi     Toyota               (B)  1:41.499 + 0.874   24
14.  Liuzzi        Force India-Mercedes (B)  1:41.675 + 1.050   20
15.  Webber        Red Bull-Renault     (B)  1:41.682 + 1.057   15
16.  Alonso        Renault              (B)  1:41.897 + 1.272   19
17.  Nakajima      Williams-Toyota      (B)  1:42.156 + 1.531   21
18.  Grosjean      Renault              (B)  1:42.213 + 1.588   19
19.  Fisichella    Ferrari              (B)  1:42.351 + 1.726   23

All timing unofficial