Sebastian Vettel suggested that Red Bull's hard late-night work might have paid off as he beat Fernando Alonso's Ferrari to the top spot in final practice for the Hungarian Grand Prix.
After Vettel was unhappy with the car on Friday, Red Bull used its first curfew exception of the year to work into the night trying to improve the set-up.
Vettel then led most of the middle part of the session this morning, having set a 1m22.021s early in the running on harder tyres. Even though he ran wide on his first flying lap on his next outing and took the best out of his tyres, he was still far enough clear of the field that he set a lap that would have been good enough for second next time around.
Alonso was then the first driver to set a good time on the super soft tyres, jumping to the front with a 1m21.469s with 10 minutes to go.
But Vettel's qualifying-style lap was even faster, the world champion clocking a 1m21.168s to end the session on top by 0.301s.
Although Jenson Button took third for McLaren, his team-mate Lewis Hamilton did not get a chance to show what he could do at the end.
The Friday pacesetter ran wide at Turn 1 at the start of what would have been his first flying lap on super softs, reported over the radio that the brakes "did not work" and pitted after one more lap. That left Hamilton in seventh.
Mark Webber was just behind Button in fourth for Red Bull, ahead of Felipe Massa - the Ferrari driving having made some small mistakes on his super soft run. He had earlier narrowly avoided the barriers at the chicane during a trip over the grass.
Nico Rosberg's Mercedes completed the top six, with Hamilton, the second Mercedes of Michael Schumacher, Vitaly Petrov's Renault and Paul di Resta's Force India next up. Nick Heidfeld was just outside the top 10 in the other Renault after losing time parked in the garage with a fuel system problem.
At the tail of the field, the Virgins and Hispanias were all outside the 107 per cent rule cut-off had it been applied to this session - although the leading drivers are unlikely to use super softs in Q1.
Pos Driver Team/Car Time Gap Laps
1. Sebastian Vettel Red Bull-Renault 1m21.168s 17
2. Fernando Alonso Ferrari 1m21.469s + 0.301s 13
3. Jenson Button McLaren-Mercedes 1m21.639s + 0.471s 14
4. Mark Webber Red Bull-Renault 1m21.645s + 0.477s 18
5. Felipe Massa Ferrari 1m22.002s + 0.834s 14
6. Nico Rosberg Mercedes 1m22.534s + 1.366s 22
7. Lewis Hamilton McLaren-Mercedes 1m22.667s + 1.499s 14
8. Michael Schumacher Mercedes 1m23.037s + 1.869s 19
9. Vitaly Petrov Renault 1m23.175s + 2.007s 19
10. Paul di Resta Force India-Mercedes 1m23.276s + 2.108s 18
11. Nick Heidfeld Renault 1m23.281s + 2.113s 13
12. Sergio Perez Sauber-Ferrari 1m23.375s + 2.207s 18
13. Kamui Kobayashi Sauber-Ferrari 1m23.626s + 2.458s 25
14. Rubens Barrichello Williams-Cosworth 1m23.663s + 2.495s 17
15. Pastor Maldonado Williams-Cosworth 1m23.894s + 2.726s 17
16. Adrian Sutil Force India-Mercedes 1m23.966s + 2.798s 18
17. Jaime Alguersuari Toro Rosso-Ferrari 1m23.998s + 2.830s 15
18. Sebastien Buemi Toro Rosso-Ferrari 1m25.061s + 3.893s 19
19. Jarno Trulli Lotus-Renault 1m25.141s + 3.973s 20
20. Heikki Kovalainen Lotus-Renault 1m25.501s + 4.333s 20
21. Jerome D'Ambrosio Virgin-Cosworth 1m26.955s + 5.787s 20
22. Daniel Ricciardo HRT-Cosworth 1m26.991s + 5.823s 19
23. Timo Glock Virgin-Cosworth 1m27.174s + 6.006s 16
24. Vitantonio Liuzzi HRT-Cosworth 1m27.713s + 6.545s 20
All timing unofficial