Chilton's Carlin entry was the very last car to cross the finish line at the end of the 30-minute session, and he was the only man to dip below the 1m29s barrier with a stunning 1m28.980s effort. Before that, he had been languishing outside the top 20 for much of the session.
James Calado (Lotus) was second fastest, just 0.023 seconds slower than Chilton's time, but will start fourth due to his two-place penalty for impeding Felipe Nasr during free practice. Calado set his best time much earlier in the session, just past the halfway mark.
Davide Valsecchi will start second for DAMS, missing out on the four points for pole by just 0.054s. Jolyon Palmer set a stunning middle sector time, but lost out in the closing yards in his iSport machine, his fourth-fastest time becoming third thanks to Calado's penalty.
Title contender Luiz Razia will start fifth for Arden, and will be relieved that Valsecchi did not get pole to erode his 10-point lead in the championship.
Giedo van der Garde was sixth, ahead of Esteban Gutierrez, Fabio Leimer, Marcus Ericsson and early pacesetter Johnny Cecotto Jr.