Sebastian Vettel set a sensational fastest time in final practice for the Spanish Grand Prix - despite only getting a single flying lap in the session due to a problem on his car.
The world champion had managed just three installation laps before an issue forced him to return to the Red Bull garage. Repairs were only completed with a few minutes to go, but his lack of running proved no impediment whatsoever as Vettel breezed straight to the top with a 1m21.707s on his only flying lap of the morning.
Until then, Vettel's team-mate Mark Webber had been in total command.
The Australian had been quickest in both sessions yesterday, and soon hit the front this morning as well, establishing a one-second margin over the field on hard tyres, and then doing the same when everyone switched to softs in the final minutes. But when Vettel emerged, Webber found himself deposed by just 0.084 seconds.
Mercedes' Michael Schumacher led the way for a while thanks to an early change to softs, and ended the session third - albeit a full 1.3s off Vettel's pace.
The McLarens were only fourth and fifth, ahead of Nico Rosberg in the second Mercedes, Sauber's Kamui Kobayashi and Renault's Vitaly Petrov.
The latter's team-mate Nick Heidfeld had the most dramatic incident of the morning when his Renault caught fire after 25 minutes. Heidfeld quickly parked the car as flames took hold around the right-hand sidepod and exhaust, and while he was unhurt, the team faces a huge job to get the car ready for qualifying.
Local hero Fernando Alonso was only ninth in the leading Ferrari, and had to park in the garage in the closing minutes after appearing to get stuck in sixth gear.
Pos Driver Team/Car Time Gap Laps
1. Sebastian Vettel Red Bull-Renault 1m21.707s 6
2. Mark Webber Red Bull-Renault 1m21.791s + 0.084s 17
3. Michael Schumacher Mercedes 1m23.057s + 1.350s 16
4. Lewis Hamilton McLaren-Mercedes 1m23.068s + 1.361s 13
5. Jenson Button McLaren-Mercedes 1m23.214s + 1.507s 14
6. Nico Rosberg Mercedes 1m23.397s + 1.690s 18
7. Kamui Kobayashi Sauber-Ferrari 1m23.669s + 1.962s 17
8. Vitaly Petrov Renault 1m24.043s + 2.336s 18
9. Fernando Alonso Ferrari 1m24.270s + 2.563s 11
10. Rubens Barrichello Williams-Cosworth 1m24.318s + 2.611s 18
11. Felipe Massa Ferrari 1m24.322s + 2.615s 17
12. Sergio Perez Sauber-Ferrari 1m24.329s + 2.622s 19
13. Pastor Maldonado Williams-Cosworth 1m24.399s + 2.692s 17
14. Sebastien Buemi Toro Rosso-Ferrari 1m24.535s + 2.828s 16
15. Adrian Sutil Force India-Mercedes 1m24.695s + 2.988s 18
16. Jaime Alguersuari Toro Rosso-Ferrari 1m24.722s + 3.015s 14
17. Paul di Resta Force India-Mercedes 1m25.223s + 3.516s 19
18. Heikki Kovalainen Lotus-Renault 1m26.236s + 4.529s 11
19. Jarno Trulli Lotus-Renault 1m27.000s + 5.293s 20
20. Timo Glock Virgin-Cosworth 1m27.706s + 5.999s 20
21. Tonio Liuzzi HRT-Cosworth 1m28.330s + 6.623s 17
22. Jerome D'Ambrosio Virgin-Cosworth 1m29.057s + 7.350s 18
23. Nick Heidfeld Renault 1m29.200s + 7.493s 6
24. Narain Karthikeyan HRT-Cosworth 1m29.562s + 7.855s 16
All timing unofficial