Webber edges Hamilton in practice

But Friday pacesetter Lewis Hamilton kept McLaren in the thick of the fight as he split the Red Bull duo and lapped just 0.017 seconds slower than Webber.

For most of the morning Hamilton looked set to complete a clean sweep of fastest practice times in Malaysia. After being stuck in traffic on his first runs, the Briton established himself at the top of the times 25 minutes into the session, usurping early pacesetter Fernando Alonso (Ferrari). A soft tyre run eight minutes later then saw Hamilton improve by a further half a second to 1m33.559s.

His rivals edged closer, but no one was able to beat the McLaren until Red Bull began its qualifying simulations in the final three minutes.

Webber immediately went to the top with a 1m33.542s, while Vettel was on course to go quicker still before hitting traffic in the final sector - leaving him 0.028s behind Hamilton and 0.045s down on Webber.

Alonso remained fourth, with the Mercedes of Michael Schumacher and Nico Rosberg completing the top six. Melbourne winner Jenson Button (McLaren) was seventh, followed by Felipe Massa's Ferrari, Rubens Barrichello's Williams and Robert Kubica's Renault.

The session was trouble-free for most drivers. Vettel had a slight problem with debris attaching itself to the front of his Red Bull, Heikki Kovalainen lost a piece of front wing from his Lotus over the kerbs, Vitaly Petrov's Renault had a run through the gravel, and Jaime Alguersuari caught a half-spin in his Toro Rosso, but otherwise final practice ran smoothly for all.

Despite fears of rain prompting teams to get on with their runs early, the forecast showers largely missed the circuit, with only slight drizzle being reported in some areas of the track. But radar forecasts suggest that much heavier rain is heading for Sepang in time for qualifying.

                                                 
Pos  Driver       Car                   Time       Gap       Laps
 1.  Webber       Red Bull-Renault      1m33.542s            17
 2.  Hamilton     McLaren-Mercedes      1m33.559s  + 0.017s  14
 3.  Vettel       Red Bull-Renault      1m33.587s  + 0.045s  17
 4.  Alonso       Ferrari               1m33.751s  + 0.209s  19
 5.  Schumacher   Mercedes              1m33.992s  + 0.450s  15
 6.  Rosberg      Mercedes              1m34.090s  + 0.548s  13
 7.  Button       McLaren-Mercedes      1m34.113s  + 0.581s  16
 8.  Massa        Ferrari               1m34.174s  + 0.632s  15
 9.  Barrichello  Williams-Cosworth     1m34.540s  + 0.998s  13
10.  Kubica       Renault               1m34.549s  + 1.007s  17
11.  Sutil        Force India-Mercedes  1m34.623s  + 1.081s  11
12.  Buemi        Toro Rosso-Ferrari    1m34.673s  + 1.131s  19
13.  Hulkenberg   Williams-Cosworth     1m34.882s  + 1.340s  13
14.  Liuzzi       Force India-Mercedes  1m34.957s  + 1.415s  16
15.  Alguersuari  Toro Rosso-Ferrari    1m35.026s  + 1.484s  16
16.  Petrov       Renault               1m35.076s  + 1.534s  17
17.  de la Rosa   Sauber-Ferrari        1m35.477s  + 1.935s  18
18.  Kobayashi    Sauber-Ferrari        1m36.404s  + 2.862s  19
19.  Glock        Virgin-Cosworth       1m37.299s  + 3.757s  15
20.  Trulli       Lotus-Cosworth        1m37.369s  + 3.827s  16
21.  Kovalainen   Lotus-Cosworth        1m38.161s  + 4.619s  18
22.  di Grassi    Virgin-Cosworth       1m38.783s  + 5.241s  13
23.  Senna        Hispania-Cosworth     1m39.868s  + 6.326s  19
24.  Chandhok     Hispania-Cosworth     1m39.895s  + 6.353s  16

All timing unofficial