Adrien Tambay was quickest in very difficult conditions in the GP3 practice session at Spa.
Practice was wet throughout, and by the end of the half hour fog was also descending over the circuit.
Manor driver Tambay emerged fastest with a 2m29.381s lap, following a late battle with Jenzer's Nico Muller and championship leader Esteban Gutierrez (ART) - beating them by half a second and one second respectively.
Tambay's team-mate Adrian Quaife-Hobbs was just behind Gutierrez in fourth, with Nigel Melker (Mucke) and Roberto Merhi (Atech CRS) completing the top six.
Pos Driver Team Time Gap
1. Adrien Tambay Manor 2m29.381s
2. Nico Muller Jenzer 2m29.940s + 0.559s
3. Esteban Gutierrez ART 2m30.424s + 1.043s
4. Adrian Quaife-Hobbs Manor 2m30.465s + 1.084s
5. Nigel Melker RSC Mucke 2m30.948s + 1.567s
6. Roberto Merhi Atech CRS 2m31.394s + 2.013s
7. Simon Trummer Jenzer 2m31.592s + 2.211s
8. Miki Monras MW Arden 2m31.683s + 2.302s
9. Vittorio Ghirelli Atech CRS 2m31.805s + 2.424s
10. Leonardo Cordeiro MW Arden 2m31.927s + 2.546s
11. Robert Wickens Status 2m32.058s + 2.677s
12. Oliver Oakes Atech CRS 2m32.064s + 2.683s
13. Daniel Juncadella Tech 1 2m32.114s + 2.733s
14. Stefano Coletti Tech 1 2m32.197s + 2.816s
15. Dean Smith Carlin 2m32.222s + 2.841s
16. Michael Christensen MW Arden 2m32.235s + 2.854s
17. Rio Haryanto Manor 2m32.258s + 2.877s
18. Antonio Felix da Costa Carlin 2m32.308s + 2.927s
19. Doru Sechelariu Tech 1 2m32.468s + 3.087s
20. Renger van der Zande RSC Mucke 2m32.653s + 3.272s
21. Josef Newgarden Carlin 2m32.665s + 3.284s
22. Tobias Hegewald RSC Mucke 2m32.776s + 3.395s
23. Daniel Morad Status 2m32.848s + 3.467s
24. Pal Varhaug Jenzer 2m33.099s + 3.718s
25. Mirko Bortolotti Addax Team 2m33.134s + 3.753s
26. Ivan Lukashevich Status 2m33.319s + 3.938s
27. Alexander Rossi ART 2m33.620s + 4.239s
28. Pablo Sanchez Lopez Addax Team 2m34.787s + 5.406s
29. Pedro Nunes ART 2m34.851s + 5.470s
30. Felipe Guimaraes Addax Team 2m39.307s + 9.926s