Kubica on top in practice 1 - Bahrain

Kubica, 21, lapped the lapped the Sakhir circuit in 1:32.170 to beat his nearest challenger by less than 0.1 seconds. Williams test driver Alex Wurz set the second fastest time.

McLaren's Finnish star Kimi Raikkonen and Ferrari's Michael Schumacher, of Germany both took to the track late in the dying minutes and finished third and fourth fastest overall, albeit over a second away from the time of Kubica.

Wurz was the first man onto the track and set the initial pace, but his run was not without drama. Wurz left his braking too late at turn 10 during one of his first flying laps and slid off the track and on to the concrete run-off area. He was able to re-join following a quick turnaround.

Scuderia Toro Rosso's Italian driver Vitantonio Liuzzi did likewise with 15 minutes of the session remaining, as did Raikkonen while on a flyer.

Super Aguri's Japanese rookie Yuji Ide, 31, encountered a mechanical problem early on that left him coasting back to the pits after a piece of bodywork had flown off his left sidepod.

World champion Fernando Alonso and his Italian Renault teammate Giancarlo Fisichella both did one slow installation lap mid-way through the session but did not register an official time.

Honda's third driver Anthony Davidson hit trouble during the session, suffering a gearbox problem after just one installation lap. The Briton, who didn't set a time, was forced to stay in the pits while the team fixed the problem ahead of the second session.

Four drivers did not leave the pits at all during the session. They were Honda racers Jenson Button and Brazilian Rubens Barrichello, and BMW-Sauber pilots Jacques Villeneuve Nick Heidfeld.

Pos  Driver        Team                     Time                  Laps
 1.  Kubica        BMW-Sauber          (M)  1:32.170               20   
 2.  Wurz          Williams-Cosworth   (B)  1:32.184  +    0.014   18 
 3.  Raikkonen     McLaren-Mercedes    (M)  1:33.388  +    1.218    6 
 4.  M.Schumacher  Ferrari             (B)  1:33.469  +    1.299    5 
 5.  Klien         Red Bull-Ferrari    (M)  1:34.800  +    2.630    6 
 6.  Jani          Toro Rosso-Cosworth (M)  1:34.831  +    2.661   15 
 7.  Montoya       McLaren-Mercedes    (M)  1:34.887  +    2.717    6 
 8.  Massa         Ferrari             (B)  1:34.925  +    2.755    6 
 9.  Coulthard     Red Bull-Ferrari    (M)  1:35.017  +    2.847    4 
10.  Liuzzi        Toro Rosso-Cosworth (M)  1:35.083  +    2.913    8 
11.  Doornbos      Red Bull-Ferrar     (M)  1:35.203  +    3.033   15 
12.  Speed         Toro Rosso-Cosworth (M)  1:35.371  +    3.201    7 
13.  Monteiro      MF1-Toyota          (B)  1:36.542  +    4.372    9 
14.  Albers        MF1-Toyota          (B)  1:36.930  +    4.760    9 
15.  Winkelhock    MF1-Toyota          (B)  1:37.918  +    5.748   16 
16.  Sato          Super Aguri-Honda   (B)  1:38.190  +    6.020   15 
17.  Ide           Super Aguri-Honda   (B)  1:40.782  +    8.612   15 
18.  Davidson      Honda               (M)  No Time                 2 
19.  Alonso        Renault             (M)  No Time                 2 
20.  Fisichella    Renault             (M)  No Time                 2 
21.  R.Schumacher  Toyota              (B)  No Time                 2 
22.  Trulli        Toyota              (B)  No Time                 1 
23.  Webber        Williams-Cosworth   (B)  No Time                 1 
24.  Rosberg       Williams-Cosworth   (B)  No Time                 1 
25.  Barrichello   Honda               (M)  No Time                   
26.  Button        Honda               (M)  No Time                   
27.  Heidfeld      BMW-Sauber          (M)  No Time                   
28.  Villeneuve    BMW-Sauber          (M)  No Time                   

All timing unofficial