Red Bull once again dominated final practice for the Spanish Grand Prix ahead of Saturday qualifying.
McLaren duo relegated to fourth and fifth
Red Bull once again dominated final practice for the Spanish Grand Prix ahead of Saturday qualifying.
Due to a problem with the Renault engine in the back of his car, world champion Sebastian Vettel did not emerge until minutes before the end of the hour-long session.
At that stage team-mate Mark Webber, quickest in both Friday's practice runs, was poised to make it a clean sweep ahead of his bid for back-to-back wins at Barcelona's Circuit de Catalunya.
With a sizzling lap of one minute 21.791secs, Webber was 1.3secs clear of Mercedes' Michael Schumacher.
Vettel, however, had other ideas on his second flying lap on soft tyres, and just as the clock had counted down to zero, he crossed the line 0.084secs quicker than Australian Webber.
Schumacher was a distant 1.350secs adrift, ahead of McLaren duo Lewis Hamilton and Jenson Button. Hamilton was 1.361secs back, with Button 1.5secs off the pace.
Nico Rosberg in his Mercedes and Sauber's Kamui Kobayashi managed to finish within two seconds of Vettel in sixth and seventh, with Renault's Vitaly Petrov eighth quickest, but 2.336secs down.
Dramatic
It was Petrov's team-mate, Heidfeld, who had the most dramatic morning as his car caught fire midway through the session.
As the flames lapped at the back of his Renault, Heidfeld rapidly pulled over at turn 10, and was equally as swift in jumping out of the car before marshals doused the fire with their extinguishers.
"It was one of the biggest fires I've had since I've been in the car," said the 176-grand prix veteran.
"We have some ideas as to what caused the fire but I don't want to speculate."
Heidfeld, who is now unlikely to compete in qualifying, added: "We just have to take the car apart. It is quite damaged on the right-hand side.
"If the chassis is damaged it's going to be a problem. It's too early to know."
Ferrari's Fernando Alonso was ninth. Team-mate Felipe Massa was 11th, with the Ferrari duo sandwiching Rubens Barrichello in his Williams, the Brazilian 2.6secs down.
