Out of sight, Lanzi had skillfully overtaken Bayliss for what looked like being the final podium position - which then began first place following the drama ahead.
Lanzi's victory was his third in WSBK, but first since 2005 - the Italian having endured two nightmare seasons with the factory squad prior to joining the satellite RG outfit for 2008.
Troy Corser completed the podium, while the third Alstare Suzuki of Fonsi Nieto - currently second to Bayliss in the world championship standings - survived the chaos ahead to climb from 13th on the grid to fourth position at flag, but he's now slipped to 34 points behind Bayliss in the title fight.
The injured Max Biaggi, who began the race in ninth position, lost out on the chance to capitalise on the incidents ahead after running down an escape road, while holding tenth place, on lap seven - dropping him to the back of the field. The Roman went on to finish out of the points in 16th.
Valencia race one
19. Lozano Ortiz