Lewis Hamilton took his first pole position of the 2009 season, as McLaren dominated the front row for the European Grand Prix at Valencia.
The Briton, who took the pole with his first attempt in Q3, was only ever threatened by his team-mate Heikki Kovalainen, who could have taken a second career pole for himself but for a mistake in the final sector of his best lap.
Rubens Barrichello will start third on the grid in the best of the Brawns, having used just one set of tyres in Q3.
Sebastian Vettel took a surprising fourth to split the Brawns, having not looked likely to do so for much of the weekend. The German, who suffered a major engine failure in the morning practice session, outpaced his title rival Button.
Luca Badoer, subbing for Felipe Massa at Ferrari, ended up last, two seconds behind team-mate Kimi Raikkonen.
Qualifying times:1 Hamilton (McLaren-Mercedes) 1:38.6492 Kovalainen (McLaren-Mercedes) 1:38.8163 Barrichello (Brawn-Mercedes) 1:39.0194 Vettel (Red Bull-Renault) 1:39.2955 Button (Brawn-Mercedes) 1:38.5316 Raikkonen (Ferrari) 1:38.8437 Rosberg (Williams-Toyota) 1:39.0398 Alonso (Renault) 1:39.1559 Webber (Red Bull-Renault) 1:38.98310 Kubica (BMW-Sauber) 1:38.80611 Heidfeld (BMW-Sauber) 1:39.03212 Sutil (Force India-Mercedes) 1:39.14513 Glock (Toyota) 1:39.45914 Grosjean (Renault) 1:39.32215 Buemi (Toro Rosso-Ferrari) 1:38.91216 Fisichella (Force India-Mercedes) 1:39.53117 Nakajima (Williams-Toyota) 1:39.79518 Trulli (Toyota) 1:39.80719 Alguersuari (Toro Rosso-Ferrari) 1:39.92520 Badoer (Ferrari) 1:41.413