Highlights - Brazilian Grand Prix qualifying
By Andrew Benson
BBC Sport in Sao Paulo
Williams driver Nico Hulkenberg took pole position for the Brazilian Grand Prix in a frantic last-lap scramble on dry-weather tyres on a damp track.
The German drove superbly to stun the title contenders and throw a wildcard into the championship battle.
Sebastian Vettel, Mark Webber, Lewis Hamilton and Fernando Alonso - the four main championship hopefuls - will line up right behind rookie Hulkenberg.
Jenson Button's hopes dimmed further after he qualified 11th.
Hulkenberg, 23, whose future at Williams is in doubt, stole a march by fitting dry-weather tyres before the drivers from the top three teams, just after team-mate Rubens Barrichello.
Vettel surprised by Hulkenberg pace
But Hulkenberg performed brilliantly to set two laps fast enough for pole, and the big names, out at the same time, failed to beat him. His best lap - one minute 14.470 seconds - was more than a second faster than Vettel's, a 1:15.519. Barrichello was sixth, 1.733secs slower than his team-mate.
Webber was just over 0.1secs behind his team-mate, with Hamilton, fourth in his McLaren, 0.228secs behind Vettel, and Alonso 0.242secs adrift of the Englishman.
Hulkenberg said: "My first pole position is an emotional and hopefully historic moment as I want to be in F1 for many, many years.
"I am still shaking from the thrill and I just want to enjoy it and get on with the job tomorrow.
"It was a pretty good lap with no mistakes. It was still tricky out there. There were wet parts, particularly the last corner. But that lap was spot on."
Vettel said: "First I thought I had missed pole by 0.1secs but then I saw there was another digit and that it was a four instead of a five."
Webber added: "He gave us all a driving lesson out there, and he found a different race track from the rest of us."
FIVE-WAY TITLE BATTLE EXPLAINED
1 ALONSO 231pts
2 WEBBER 220pts
3 HAMILTON 210pts
4 VETTEL 206pts
5 BUTTON 189pts
If Alonso wins in Brazil, he will be champion unless Webber is higher than fifth
If Alonso is second, he will be champion unless Webber is higher than eighth, Hamilton higher than fourth or Vettel wins
If Alonso is third, he will be champion unless Webber finishes in the top 10, Hamilton in the top four and Vettel in the top three
If Alonso does not finish on the podium, it will go to Abu Dhabi
Button can only stay in contention if he finishes first or second but is out if Alonso finishes in the top six or if Webber is in the top two
Vettel must beat Alonso on track to stay in contention
Asked about starting the race ahead of all the title contenders, Hulkenberg said: "The best thing would be to drive off into the distance, but obviously that is not going to happen."
His race engineer, Tom McCullough, denied that Hulkenberg had been a wet-weather set-up, which would have given him an advantage in qualifying, but a handicap in the forecasted dry race.
"This is our fully dry set-up," McCullough told BBC Sport. "If you look at the data, he's very committed, especially in the high-speed corners. He's very good in changeable conditions.
"Hopefully, with track position, we can fight with the Red Bulls, McLaren and Ferrari, but good points is what we are after. Anything else is a bonus."
It is the first pole position for Williams since the 2005 European Grand Prix, when Nick Heidfeld took the position, exactly 100 races ago.
Barrichello was ahead of Renault's Robert Kubica, Mercedes' Michael Schumacher - unusually ahead of team-mate Nico Rosberg - Ferrari's Felipe Massa and the second Renault of Vitaly Petrov.
Alonso heads into the race as championship leader, 11 points ahead of Webber, with Hamilton a further 10 points adrift.
Vettel is 25 points - one win - behind Alonso with only 50 remaining in the final two races here and in Abu Dhabi next weekend. Button is fifth, 42 points behind.
Alonso was calm about being last out of the top four championship hopefuls.
Alonso satisfied with qualifying performance
"In qualifying like this you can never make any predictions or expectations," the Spaniard said.
"We were struggling with intermediates and with dry tyres it was a difficult circuit to play.
"My last lap was a little bit quicker (initially), but I lost some 10ths at one of the corners. The dry line was not very wide, and if you go off it, you lose a lot of time.
"I guess maybe in those conditions only Nico did a perfect lap, all the others we lose a little bit here and a little bit there. It is the way it is.
"The championship is not really in my mind. You can get some strange results but we are concentrating on increasing the gap and if we give away points, making sure it is not too many."
Button came as close as he has yet to admitting that his hopes are over and that his role now is to support Hamilton.
Button struggled to find balance
He said: "It has been pretty tough all weekend. The car was actually better in qualifying. But I have qualified further down here and finished all right. It is hard to play a supporting role from there."
Team-mate Hamilton was slightly more upbeat about his fourth place, saying: "It is better than nothing. I have often started fourth here, it is not my favourite, but I can't complain.
"In qualifying I just got held up on that last corner which is frustrating, but we are still in the fight. We have got good race pace and straight speed and I'm happy I can battle in there."
Heavy overnight rain had left the track wet in the morning, and it continued to rain intermittently until it abated shortly before the start of practice at 1100 local time (1300 GMT).
It was raining at the start of first qualifying but it soon abated, and the track dried through the session to the point that the drivers were able to put on slick tyres for the all-important last runs in the third session.
Alonso set the pace in the first, his lap of 1:18.987 just edging out Webber and Vettel, but the Red Bulls were at the front in the second session, Webber again ahead of Vettel.
Kubica was third in Q2, ahead of Hamilton, Michael Schumacher, Rubens Barrichello and Alonso.
Hulkenberg's pole was the first for a Cosworth engine since Barrichello in a Stewart at the 1999 French Grand Prix. After qualifying, Rosberg complained to the stewards that he had been blocked by Sebastien Buemi, claiming this had prevented him from reaching Q3, but after scrutiny the complaint was dismissed.
Toro Rosso's Beumi qualified in 15th but is set to start from 20th because of a five-place grid penalty he incurred at the Korean Grand Prix.
Top three drivers - Brazilian GP qualifying