Mark Webber beat Red Bull team-mate Sebastian Vettel to Korean Grand Prix pole position as the Australian's last lap upstaged the hitherto dominant world champion.
Vettel had looked unstoppable until the final seconds of qualifying.
Fastest in Q1 and Q2, his first Q3 lap was three tenths of a second clear of the opposition.
But then Webber, who had been third in the provisional order, found a half-second improvement on his last pole attempt to set a 1m37.242s. The result was also the 200th Formula 1 pole for Red Bull's engine supplier Renault.
Vettel's response was simply not quick enough, with a poor first sector preventing him from improving on his earlier mark. That ensured pole for Webber by 0.074s, despite his potentially costly practice problems.
Fernando Alonso had held the outside front row grid spot after the first Q1 runs, but Webber's leap and an improvement from Lewis Hamilton's McLaren pushed the championship leader's Ferrari back to fourth.
Lotus showed better form than of late as Kimi Raikkonen and Romain Grosjean took fifth and seventh in their upgraded cars, either side of Ferrari's Felipe Massa.
Nico Hulkenberg took his Force India to eighth, beating the Mercedes of Nico Rosberg and Michael Schumacher.
There could have been several surprises in the early part of qualifying, but in the end the only major upset was that Jenson Button did not make Q3.
The McLaren driver's first Q2 lap was compromised by an error, and then he missed the cut by 0.005s when he had to back off on his second shot as yellows flew for Daniel Ricciardo's Toro Rosso parking with a gearbox problem.
Had the end of Q1 worked out very slightly differently, neither McLaren would have reached the top 10. Hamilton was one of few drivers not to use super softs in Q1, and as others found big gains on the quicker rubber, his early time was shoved back to 17th place.
The McLaren was sat in the pits and could not respond, but escaped a shock elimination as Bruno Senna's final lap was not good enough, leaving the Williams down with the Caterhams, Marussias and HRTs. Senna's team-mate Pastor Maldonado fared only marginally better, qualifying 15th.
Alonso did use super softs and make two runs in Q1, yet that was only good enough for 16th. There were no such scares for either Hamilton or Alonso in Q2, though.
Sauber had to settle for 12th and 13th this week, while Paul di Resta blamed traffic as his Force India ended up only 14th.
At the very back, Narain Karthikeyan did not set a time due to brake problems with his HRT.
Pos Driver Team Time Gap 1. Mark Webber Red Bull-Renault 1m37.242s 2. Sebastian Vettel Red Bull-Renault 1m37.316s + 0.074 3. Lewis Hamilton McLaren-Mercedes 1m37.469s + 0.227 4. Fernando Alonso Ferrari 1m37.534s + 0.292 5. Kimi Raikkonen Lotus-Renault 1m37.625s + 0.383 6. Felipe Massa Ferrari 1m37.884s + 0.642 7. Romain Grosjean Lotus-Renault 1m37.934s + 0.692 8. Nico Hulkenberg Force India-Mercedes 1m38.266s + 1.024 9. Nico Rosberg Mercedes 1m38.361s + 1.119 10. Michael Schumacher Mercedes 1m38.513s + 1.271 Q2 cut-off time: 1m38.436s Gap ** 11. Jenson Button McLaren-Mercedes 1m38.441s + 0.674 12. Sergio Perez Sauber-Ferrari 1m38.460s + 0.693 13. Kamui Kobayashi Sauber-Ferrari 1m38.594s + 0.827 14. Paul di Resta Force India-Mercedes 1m38.643s + 0.876 15. Pastor Maldonado Williams-Renault 1m38.725s + 0.958 16. Daniel Ricciardo Toro Rosso-Ferrari 1m39.084s + 1.317 17. Jean-Eric Vergne Toro Rosso-Ferrari 1m39.340s + 1.573 Q1 cut-off time: 1m39.180s Gap * 18. Bruno Senna Williams-Renault 1m39.443s + 1.235 19. Vitaly Petrov Caterham-Renault 1m40.207s + 1.999 20. Heikki Kovalainen Caterham-Renault 1m40.333s + 2.125 21. Charles Pic Marussia-Cosworth 1m41.317s + 3.109 22. Timo Glock Marussia-Cosworth 1m41.371s + 3.163 23. Pedro de la Rosa HRT-Cosworth 1m42.881s + 4.673 24. Narain Karthikeyan HRT-Cosworth no time 107% time: 1m45.082s
* Gap to quickest in Q1
** Gap to quickest in Q2