Jenson Button finally secured his first pole position for McLaren with a stunning performance in Belgian Grand Prix qualifying.
Kamui Kobayashi claimed his first front-row start as he underlined Sauber's speed with a shock second place, while world champion Sebastian Vettel failed to make it out of Q2.
Button put himself eight tenths clear of the field for much of Q2, then repeated that speed to deliver a 1m47.686s early in Q3. One of the few drivers to do two Q3 runs, he found even more time at the second attempt and delivered a 1m47.573s.
Kobayashi was three tenths adrift as he secured his career-best Formula 1 start. Team-mate Sergio Perez also shone in fifth place.
Q1 pacesetter Pastor Maldonado was another star underdog as he took third for Williams, although an impeding incident involving the Venezuelan and 12th-place qualifier Nico Hulkenberg is under investigation.
Pre-race favorite Lotus only managed fourth with Kimi Raikkonen and ninth with Romain Grosjean. The latter had a few scares just getting out of Q1 following a mistake and traffic issues with an HRT.
World championship leader Fernando Alonso could not repeat his morning practice performance and starts sixth.
As one McLaren took pole, the other was only eighth quickest, although Lewis Hamilton will gain a place when Mark Webber's Red Bull is demoted five places from seventh due to a gearbox change penalty. Force India's Paul di Resta completed the top 10.
Vettel was the most significant casualty of a close Q2. Just two tenths separated him from Red Bull teammate Webber, but that translated to seven positions, as last year's Spa poleman and race winner ended up only 11th, 0.012s off a Q3 spot.
He was not the only big name to miss out. Felipe Massa trailed the sister Ferrari of Alonso by seven tenths as he struggled to 14th, behind Michael Schumacher, whose 13th place was the best Mercedes could manage on a tough afternoon.
Already carrying a five-place grid penalty for a gearbox change following his morning failure, Nico Rosberg was only 18th in qualifying after crossing the line moments too late for a final Q1 run.
Rosberg's disappointment meant both Toro Rossos reached Q2, where they beat the Williams of Bruno Senna. The Brazilian pulled off an incredible save after sliding broadside across the kerbs through most of Pouhon, then had to pit for repairs and could not get above 17th when he rejoined.
At the back, Timo Glock used Marussia's upgrades to get a little closer to the Caterhams, but his teammate Charles Pic was beaten to 22nd by Pedro de la Rosa's HRT.
Pos Driver Car Time Gap
1. Jenson Button McLaren-Mercedes 1m47.573s
2. Kamui Kobayashi Sauber-Ferrari 1m47.871s + 0.298s
3. Pastor Maldonado Williams-Renault 1m47.893s + 0.320s
4. Kimi Raikkonen Lotus-Renault 1m48.205s + 0.632s
5. Sergio Perez Sauber-Ferrari 1m48.219s + 0.646s
6. Fernando Alonso Ferrari 1m48.313s + 0.740s
7. Mark Webber Red Bull-Renault 1m48.392s + 0.819s***
8. Lewis Hamilton McLaren-Mercedes 1m48.394s + 0.821s
9. Romain Grosjean Lotus-Renault 1m48.538s + 0.965s
10. Paul di Resta Force India-Mercedes 1m48.890s + 1.317s
Q2 cut-off time: 1m48.993s Gap *
11. Sebastian Vettel Red Bull-Renault 1m49.722s + 0.472s
12. Nico Hulkenberg Force India-Mercedes 1m49.362s + 0.112s
13. Michael Schumacher Mercedes 1m49.742s + 0.492s
14. Felipe Massa Ferrari 1m49.588s + 0.338s
15. Jean-Eric Vergne Toro Rosso-Ferrari 1m49.763s + 0.513s
16. Daniel Ricciardo Toro Rosso-Ferrari 1m49.572s + 0.322s
17. Bruno Senna Williams-Renault 1m49.958s + 0.708s
Q1 cut-off time: 1m50.126s Gap **
18. Nico Rosberg Mercedes 1m50.181s + 1.188s***
19. Heikki Kovalainen Caterham-Renault 1m51.739s + 2.746s
20. Vitaly Petrov Caterham-Renault 1m51.967s + 2.974s
21. Timo Glock Marussia-Cosworth 1m52.336s + 3.343s
22. Pedro de la Rosa HRT-Cosworth 1m53.030s + 4.037s
23. Charles Pic Marussia-Cosworth 1m53.493s + 4.500s
24. Narain Karthikeyan HRT-Cosworth 1m54.989s + 5.996s
107 per cent time: 1m56.622s
* Gap to fastest in Q2
** Gap to fastest in Q3
*** Will take five-place penalty