Nick Heidfeld responded to his team's call for him to raise his game by posting the quickest time in testing on day two.

The BMW Sauber driver had been told his performances this season had not been good enough with the German put in the shade by the form of Polish team-mate Robert Kubica.

Heidfeld set a best lap of one minute 22.621 seconds at the Italian circuit ahead of next month's Italian Grand Prix.

Williams driver Nico Rosberg was second quickest and McLaren's Heikki Kovalainen was third.

Toro Rosso's Sebastian Vettel was fourth fastest ahead of Ferrari's Felipe Massa who had been quickest on day one.

Renault's Fernando Alonso was sixth fastest ahead of Adrian Sutil (Force India), Mark Webber (Red Bull), Jarno Trulli (Toyota), Sebastien Bourdais (Toro Rosso) and the Honda duo of Rubens Barrichello and Jenson Button.