Mark Webber has beaten Sebastian Vettel for the first time this season. The Red Bull driver was two tenths faster than his team-mate in Barcelona and claimed his first pole position of 2011.
As in Turkey, both wriggled out of their cockpits well before the end of Q3, thus depriving the crowd of a thrilling internal battle for pole.
"Sebastian didn't have the use of KERS during the whole of qualifying whereas Mark did, so it would have been an unequal contest," said team boss Christian Horner. "It made more sense to save tyres for the race than to compete against each other."
Lewis Hamilton finished in third place ahead of Fernando Alonso and team-mate Jenson Button. Nico Rosberg posted the seventh-fastest time. Michael Schumacher saved his tyres and settled for tenth.
Nick Heidfeld didn't even manage to get out on track after his R31 caught fire from a broken exhaust in the third practice session. Despite a herculean effort, the mechanics lost the race against time and were unable to repair the car for the afternoon session.
"Unfortunately, we couldn't get the car fixed in time for qualifying," said Heidfeld. "That was the biggest fire I've experienced in my whole F1 career. A lot of components were destroyed."
"It might be easier to make progress from the back. We've seen that in a couple of recent races. A spectacular example being Mark Webber in Shanghai. Of course, he's sitting in a Red Bull, but I think we're still in with a good chance."
This means that the drivers who failed to clear the 107-percent threshold may also be allowed to start tomorrow.