Control supplier Pirelli mandated soft-compound option rubber for this event, two steps ahead of the 'hard' prime, which meant drivers used it like a qualifying tyre. This, coupled with the benefit of the Formula 1 rubber laid down from free practice, meant that 25 of the 26 cars took to the track immediately - only practice pacesetter Josef Kral eschewing this option by staying in the pits, and ending up 16th on the grid.
Tom Dillmann was one of the first of the frontrunners on a flying lap, but spun at the right-hander before the chicane on the crucial lap for the bulk of the field. Yellow flags ruined the laps of the majority of those behind him, with the late-out James Calado taking the most advantage, setting a 1m30.655s after Dillmann had got going again.
Also taking full advantage of this strange situation was Trident's Stephane Richelmi - who starts third despite not having scored a point all season - and Carlin's Max Chilton in fourth. Many expected frontrunners found the tyres had gone off before a second quick lap was possible, and were forced to revert to primes to try and move up the grid.
Arden's Luiz Razia, second in the points, went for the strategy of a prime-tyre first run, which netted 12th, and saved his option tyres for his second attempt. He came across three cars on out-laps, however, and a poor final sector meant he did not improve his time, and dropped to 13th by the end of the session.
Racing Engineering's Fabio Leimer also took this strategy, and from fourth on his prime-tyred run, he improved his time with seven minutes remaining to grab the second spot on the front row on his option tyres. His 1m30.865s was 0.210 seconds down on Calado's pace.
Giedo van der Garde will start fifth for Caterham Racing, ahead of Scuderia Coloni's Fabio Onidi.
Points leader Davide Valsecchi will start seventh. He lapped in 1m31.212s on options, and almost matched it with a prime-booted 1m31.285s in his DAMS car. He appeared to be baulked by Calado's team-mate Esteban Gutierrez at one point late in the session - Gutierrez will start down in 11th.
The session ended with Simon Trummer in the gravel at Turn 4 in his Arden machine.
1. James Calado Lotus 1m30.655s
2. Fabio Leimer Racing Engineering 1m30.865s + 0.210s
3. Stephane Richelmi Trident 1m30.902s + 0.247s
4. Max Chilton Carlin 1m30.962s + 0.307s
5. Giedo van der Garde Caterham 1m31.006s + 0.351s
6. Fabio Onidi Coloni 1m31.167s + 0.512s
7. Davide Valsecchi DAMS 1m31.212s + 0.557s
8. Stefano Coletti Coloni 1m31.212s + 0.557s
9. Jolyon Palmer iSport 1m31.269s + 0.614s
10. Nathanael Berthon Racing Engineering 1m31.308s + 0.653s
11. Esteban Gutierrez Lotus 1m31.320s + 0.665s
12. Nigel Melker Ocean 1m31.332s + 0.677s
13. Luiz Razia Arden 1m31.377s + 0.722s
14. Marcus Ericsson iSport 1m31.391s + 0.736s
15. Johnny Cecotto Addax 1m31.565s + 0.910s
16. Josef Kral Addax 1m31.599s + 0.944s
17. Fabrizio Crestani Lazarus 1m31.677s + 1.022s
18. Tom Dillmann Rapax 1m31.682s + 1.027s
19. Simon Trummer Arden 1m31.939s + 1.284s
20. Rodolfo Gonzalez Caterham 1m31.966s + 1.311s
21. Victor Guerin Ocean 1m32.270s + 1.615s
22. Felipe Nasr DAMS 1m32.325s + 1.670s
23. Julian Leal Trident 1m32.691s + 2.036s
24. Rio Haryanto Carlin 1m33.010s + 2.355s
25. Ricardo Teixeira Rapax 1m33.083s + 2.428s
26. Giancarlo Serenelli Lazarus 1m33.329s + 2.674s