BARCELONA, Spain, April 26, 2008 (AFP) - German Nick Heidfeld maintained BMW´s impressive progress this season when he topped the times in Saturday morning´s final practice for Sunday´s Spanish Grand Prix.

The 30-year-old driver from Moenchengladbach clocked a fastest time of one minute and 21.269 seconds on soft compound tyres at the end of the session to leap from 19th to the leading position.

This put him nearly two-tenths of a second ahead of Scot David Coulthard, in a Red Bull, and three seconds clear of ever-improving Spaniard Fernando Alonso in his Renault.

Poland´s Robert Kubica was fourth in the second BMW and Italian Jarno Trulli fifth in a Toyota.

But the session could not be evaluated as a signal of what lies ahead this weekend in Sunday´s showdown at the Circuit de Catalunya because it appeared that both Ferrari and McLaren ran with heavy fuel loads and in readiness for the race rather than Saturday afternoon´s qualifying session.

Brazilian Felipe Massa and Finn Kimi Raikkonen were only ninth and 13th respectively for Ferrari while McLaren, continuing their enigmatic performance this weekend, claimed 11th and 15th places through Briton Lewis Hamilton and Finn Heikki Kovalainen.

Sebastien Bourdais of France was a surprise sixth for Toro Rosso, ahead of double world champion Alonso´s Renault team-mate Nelson Piquet of Brazil and Honda driver Briton Jenson Button.

Behind Massa, German Timo Glock took the final top ten spot in the second Toyota.

Australian Mark Webber failed to set a time in the second Red Bull. A suspected throttle problem caused his car to come to a halt in the pit exit before he could complete a flying lap.

As on Friday, the braking area for the tight Turn 10 was the scene of the session´s main incidents, with both Brazilian Rubens Barrichello in his Honda and Force India´s German driver Adrian Sutil spinning down the asphalt run-off.