Alain Menu edged out Chevrolet team-mates Yvan Muller and Rob Huff in an eventful second practice session on the streets of Marrakech.
Times tumbled throughout the 30 minutes and the lead changed hands almost as often as the stewards were called into action, made busy by a multitude of spins and track limit violations.
With five minutes of the session remaining Muller was the only Chevrolet driver in the top three, sitting third behind the Lukoil SEAT of Gabriele Tarquini and its Tuenti independent sister car of Pepe Oriola.
Muller improved to go fastest with three minutes to go, only to be displaced as Alain Menu set a new benchmark - a 1m44.927s - as the flag fell.
Huff too improved on his final tour to go third fastest and complete what had appeared an unlikely Chevrolet 1-2-3.
That pushed Tarquini down to fourth and Oriola - the top Yokohama Independent - to fifth.
Arena's strong form continued as Tom Chilton captured sixth in the Ford S2000TC, the Briton having been above Huff and in fifth until the final minutes.
The session was halted temporarily as Mehdi Bennani's stricken Proteam BMW limped its way through the first sector, the Moroccan going so slowly that the red flags flew until he could crawl to the nearest track exit.
Bennani had also spun and rejoined earlier in the session, one of several drivers to do so as the WTCC field began to push the limits of the 4.5km circuit.
Stefano D'Aste (Wiechers BMW), Charles Ng and Franz Engstler (both Engstler BMW), were among the other culprits, although D'Aste and Engstler were still to finish seventh and eighth respectively.
There were also track warnings for Tarquini, Menu and Muller - among others - while bamboo Chevrolet's Alex MacDowall had his eighth lap struck from the timesheets.
He ended the session 10th fastest, behind the second Arena Ford of James Nash.
Pos Driver Team/Car Time Gap
1. Alain Menu Chevrolet 1m44.927s
2. Yvan Muller Chevrolet 1m45.126s + 0.199s
3. Rob Huff Chevrolet 1m45.198s + 0.271s
4. Gabriele Tarquini Lukoil SEAT 1m45.222s + 0.295s
5. Pepe Oriola Tuenti SEAT 1m45.400s + 0.473s
6. Tom Chilton Arena Ford 1m45.532s + 0.605s
7. Stefano D'Aste Wiechers BMW 1m46.106s + 1.179s
8. Franz Engstler Engstler BMW 1m46.177s + 1.250s
9. James Nash Arena Ford 1m46.331s + 1.404s
10. Alex MacDowall bamboo Chevrolet 1m46.346s + 1.419s
11. Tom Coronel ROAL BMW 1m46.460s + 1.533s
12. Tiago Monteiro Tuenti SEAT 1m46.477s + 1.550s
13. Norbert Michelisz Zengo BMW 1m46.972s + 2.045s
14. Darryl O'Young Special Tuning SEAT 1m47.049s + 2.122s
15. Mehdi Bennani Proteam BMW 1m47.153s + 2.226s
16. Tom Boardman Special Tuning SEAT 1m47.157s + 2.230s
17. Pasquale di Sabatino bamboo Chevrolet 1m47.376s + 2.449s
18. Charles Ng Engstler BMW 1m47.461s + 2.534s
19. Alberto Cerqui ROAL BMW 1m47.820s + 2.893s
20. Isaac Tutumlu Proteam BMW 1m48.533s + 3.606s
21. Andrea Barlesi SUNRED SEAT 1m49.306s + 4.379s
22. Aleksei Dudukalo Lukoil SEAT 1m49.483s + 4.556s