Kubica quickest in practice

Kubica led the way after posting a time of one minute 25.613 seconds with Heidfeld trailing his team-mate by 0.337secs.

Fernando Alonso was third, just under half a second off the pace, suggesting he may fare better in his Renault this weekend than widely predicted, while Williams driver Nico Rosberg finished fourth.

But the leading contenders were conspicuous by their absence at the top of the timesheets.

Ferrari driver Felipe Massa's 11th position proved to be the best of them, while McLaren's Lewis Hamilton was in close attendance in 12th, but both drivers were nearly a second and a half behind Kubica.

Defending world champion Kimi Raikkonen was 14th in the second Ferrari, while Heikki Kovalainen trailed in 20th, beating only the Super Aguris of Takuma Sato and Anthony Davidson, who was dead last.

It was stark contrast to yesterday's running, when Raikkonen had been fastest in the morning session and Hamilton the top man in the afternoon.

However, the real test is still to come as the afternoon's qualifying session will give a more realistic picture of who will be the main protagonists during Sunday's 58-lap showdown.

David Coulthard and Mark Webber maintained Red Bull's consistent showings with fifth and sixth respectively, while Jenson Button claimed an encouraging seventh in his Honda and Sebastian Vettel eighth.