Alonso tops final practice in Singapore

In a repeat of his practice two performance, the Renault driver vaulted up the order with an aggressive late lap, setting a 1:44.506 after 58 minutes.

Alonso's effort on soft tyres gave him a comfortable margin over the rest of the field, as he beat second-placed Lewis Hamilton's McLaren by six tenths of a second.

Felipe Massa was third for Ferrari, but the Brazilian set his best time on the harder tyres, and was only 0.127 seconds adrift of Hamilton.

Nelson Piquet claimed fourth in the second Renault, having led the way until the final few minutes, with Williams' Nico Rosberg impressed again in fifth, and Ferrari's Kimi Raikkonen languishing in 17th after an error.

Monza winner Sebastian Vettel led the way for much of the hour in his Toro Rosso, having leapt to the top by a comfortable margin with his first flying lap of the session. The German stayed ahead until the 35-minute mark, when Piquet beat his time by four tenths of a second.

Piquet remained on top going into the late soft tyre runs, when he was pushed back to fourth by Alonso, Hamilton and Massa.

Rosberg maintained his strong Friday pace to move into fifth at the end of the session, ahead of another eye-catching performance from Honda's Jenson Button, who ran as high as second after making an early switch to soft tyres.

It was another unhappy session for struggling world champion Raikkonen, who locked up and slid off-course at Turn 7. The Finn tried in vain to turn his undamaged Ferrari around in the escape road before eventually having to admit defeat and park the car, ending his session with 15 minutes remaining.

Giancarlo Fisichella had a more destructive incident when he became the first man to crash a Formula One car at the much-debated Turn 10 chicane. The Force India driver misjudged the corner and was launched over the controversial kerbs and into the barriers, causing significant right-front damage to his car.

Red Bull's problems continued, with David Coulthard's car jamming in third gear on the installation lap, forcing him to stay in the garage until the final three minutes.

His teammate Mark Webber made two visits to the escape road at Turn 18, where he had crashed on Friday, but avoided contact this time and completed the session in eighth, behind Robert Kubica (BMW), and ahead of Vettel and his Toro Rosso teammate Sebastien Bourdais.

Heikki Kovalainen only managed 13th in the second McLaren, having narrowly avoided the wall when he made a mistake on his final flying lap.

Pos  Driver        Team                     Time              Laps
 1.  Alonso        Renault             (B)  1:44.506           19
 2.  Hamilton      McLaren-Mercedes    (B)  1:45.119 + 0.613   13
 3.  Massa         Ferrari             (B)  1:45.246 + 0.740   16
 4.  Piquet        Renault             (B)  1:45.249 + 0.743   18
 5.  Rosberg       Williams-Toyota     (B)  1:45.386 + 0.880   17
 6.  Button        Honda               (B)  1:45.409 + 0.903   20
 7.  Kubica        BMW Sauber          (B)  1:45.425 + 0.919   17
 8.  Webber        Red Bull-Renault    (B)  1:45.450 + 0.944   21
 9.  Vettel        Toro Rosso-Ferrari  (B)  1:45.477 + 0.971   19
10.  Bourdais      Toro Rosso-Ferrari  (B)  1:45.599 + 1.093   18
11.  Heidfeld      BMW Sauber          (B)  1:45.689 + 1.183   19
12.  Nakajima      Williams-Toyota     (B)  1:45.982 + 1.476   18
13.  Kovalainen    McLaren-Mercedes    (B)  1:45.982 + 1.476   13
14.  Barrichello   Honda               (B)  1:46.073 + 1.567   21
15.  Glock         Toyota              (B)  1:46.180 + 1.674   23
16.  Trulli        Toyota              (B)  1:46.221 + 1.715   19
17.  Raikkonen     Ferrari             (B)  1:46.482 + 1.976   10
18.  Coulthard     Red Bull-Renault    (B)  1:46.794 + 2.288    6
19.  Fisichella    Force India-Ferrari (B)  1:47.166 + 2.660   14
20.  Sutil         Force India-Ferrari (B)  1:47.727 + 3.221   19

All timing unofficial