JOIN USButton grabs pole in Barcelona
"I wished to have the pole but at the last minute he took it away," said the disappointed German, the only driver other than Brawn GP's Briton to have won this season.
Button now has a good chance to take his fourth victory in five races, knowing the driver on pole has won in Barcelona for the past eight years and 13 times in the past 14 at the Circuit de Catalunya.
Team-mate Rubens Barrichello qualified third, with Felipe Massa alongside on an all-Brazilian second row for revived champions Ferrari.
Button left it late before heading out for his final flying lap, the 29-year-old leaving himself no room for error in making it round the track before the session ended.
"It could have gone very, very wrong," he said. "I think I just got across the line with a couple of seconds to spare."
Button won from pole in Australia and Malaysia but had not qualified in the top three for the past two races.
Saturday's was the sixth pole of his career.
Australian Mark Webber was fifth quickest for Red Bull, Brawn's closest rivals, just ahead of the Toyotas of Timo Glock and Jarno Trulli who could give the table topper a run for his money.
Spain's double World champion Fernando Alonso will start eighth for Renault, and that it is his home circuit will give him an added edge in the morrow’s race.
While Massa, who will get a boost at the start from the KERS energy recovery system that the cars ahead of him do not have, could be pleased with his afternoon's work there were still red faces at Ferrari.
Finland's Kimi Raikkonen, the 2007 World champion who won in Barcelona last year, qualified only 16th.
McLaren also had a nightmare day with Britain's World champion Lewis Hamilton 14th and team-mate Heikki Kovalainen 18th.
Spanish GP starting grid
Driver Country Team
1. Jesnson Button Britain Brawn GP
2. Sebastian Vettel Germany Red Bull
3. Rubens Barrichello Brazil Brawn GP
4. Felippe Massa Brazil Ferrari
5. Mark Webber Australia Red Bull
6. Timo Glock Germany Toyota
7. Jarno Trulli Italy Toyota
8. Fernando Alonso Spain Renault
9. Nico Rosberg Germany Williams
10. Robert Kubica Poland BMW Sauber
Others: 11. Kazuki Nakajima (Williams), 12. Nelson Piquet (Renault), 13. Nick Heidfeld (BMW-Sauber), 14. Lewis Hamilton (McLaren), 15. Sebastien Buemi (Toro Rosso), 16. kimi Raikkonen (Ferrari), 17. Sebastien Bourdais Toro Rosso), 18. Heiki Kovalainen (McLaren), 19. Adrian Sutil (Force India), 20. G Fisichella (Force India).