Lewis Hamilton claimed his fourth pole position of the Formula 1 season as he led Jenson Button in an all-McLaren front row in qualifying for the Italian Grand Prix.
Having led both second and third practice, Hamilton maintained his strong form to set a 1m24.010s at the start of Q3. That proved unbeatable, and Button eventually joined him up front with a lap 0.123 second slower.
Button's run deposed Felipe Massa, as the Ferrari driver delivered his best qualifying performance of the year. But it was a disastrous session for Massa's championship-leading teammate Fernando Alonso, who was only 10th, 1.4sec slower. Ferrari reported a suspected anti-rollbar failure.
Paul di Resta qualified a superb fourth, although he will move down to ninth when a gearbox-change penalty is applied. The Scot's speed will still be some consolation for Force India as his teammate Nico Hulkenberg encountered an apparent gearbox problem at the start of Q1 and was left at the back of the field.
Red Bull had another muted qualifying session. Sebastian Vettel was sixth, while his teammate Mark Webber did not make Q3, missing the cut by 0.067sec as he took 11th.
Mercedes' Michael Schumacher and Nico Rosberg sandwich Vettel in fifth and seventh. Kimi Raikkonen qualified eighth for Lotus, ahead of Kamui Kobayashi's Sauber.
It was also a tough day for Williams. A mistake on the exit of the Ascaris left Pastor Maldonado 12th in Q2, which will become 22nd on the grid due to his Spa penalties. Bruno Senna was only 14th in the sister car.
Romain Grosjean's substitute Jerome d'Ambrosio was around 0.7sec off teammate Raikkonen's pace throughout qualifying, which left him 16th for his Lotus debut.
D'Ambrosio substitute had a brief scare in Q1 when an error on his first run left him behind Heikki Kovalainen's Caterham and in danger of elimination, but he switched to the softer tires and made the cut with his last attempt.
Pos Driver Car Time Gap
1. Lewis Hamilton McLaren-Mercedes 1m24.010s
2. Jenson Button McLaren-Mercedes 1m24.133s + 0.123s
3. Felipe Massa Ferrari 1m24.247s + 0.237s
4. Paul di Resta Force India-Mercedes 1m24.304s + 0.294s***
5. Michael Schumacher Mercedes 1m24.540s + 0.530s
6. Sebastian Vettel Red Bull-Renault 1m24.802s + 0.792s
7. Nico Rosberg Mercedes 1m24.833s + 0.823s
8. Kimi Raikkonen Lotus-Renault 1m24.855s + 0.845s
9. Kamui Kobayashi Sauber-Ferrari 1m25.109s + 1.099s
10. Fernando Alonso Ferrari 1m25.678s + 1.668s
Q2 cut-off time: 1m24.742s Gap *
11. Mark Webber Red Bull-Renault 1m24.809s + 0.567s
12. Pastor Maldonado Williams-Renault 1m24.820s + 0.578s****
13. Sergio Perez Sauber-Ferrari 1m24.901s + 0.659s
14. Bruno Senna Williams-Renault 1m25.042s + 0.800s
15. Daniel Ricciardo Toro Rosso-Ferrari 1m25.312s + 1.070s
16. Jerome d'Ambrosio Lotus-Renault 1m25.408s + 1.166s
17. Jean-Eric Vergne Toro Rosso-Ferrari 1m25.441s + 1.199s
Q1 cut-off time: 1m25.834s Gap **
18. Heikki Kovalainen Caterham-Renault 1m26.382s + 2.207s
19. Vitaly Petrov Caterham-Renault 1m26.887s + 2.712s
20. Timo Glock Marussia-Cosworth 1m27.039s + 2.864s
21. Charles Pic Marussia-Cosworth 1m27.073s + 2.898s
22. Narain Karthikeyan HRT-Cosworth 1m27.441s + 3.266s
23. Pedro de la Rosa HRT-Cosworth 1m27.629s + 3.454s
24. Nico Hulkenberg Force India-Mercedes
107 per cent time: 1m30.076s
* Gap to fastest in Q2
** Gap to fastest in Q3
*** Will take five-place penalty
**** Will take 10-place penalty
All timing unofficial