MELBOURNE, March 15, 2008 (AFP) - BMW Sauber pair Robert Kubica and Nick Heidfeld were fastest in final practice ahead of Saturday´s qualifying for the Formula One season-opener at the Australian Grand Prix.

Poland´s Kubica, who has one podium finish in 22 GPs, posted a fastest lap time of one minute 25.613 seconds.

Kubica was ahead of teammate Heidfeld, who swept around the circuit in 1:25.950.

Renault´s dual world champion Fernando Alonso was third-fastest in 1:26.082 ahead of German Nico Rosberg in a Williams at 1:26.171, Red Bull´s David Coulthard (1:26.385) and Australian Mark Webber (1:26.407).

The big guns of Ferrari and McLaren were down the times, with world champion Kimi Raikkonen ranked 14th at 1:27.163 and his McLaren title rival Lewis Hamilton 12th with 1:27.084.

Ferrari´s No.2 driver Felipe Massa clocked 1:27.020 for 11th best.

The one-off qualifying takes place later Saturday to determine grid positions for Sunday´s race.