Dean Berta Vinales, Alejandro Carrion, Daniel Mogeda, Harry Khouri and Yeray Ruiz were involved in a major crash at Turn 2 at the start of lap 11, prompting race officials to red flag the session.
The race was not restarted and the results were declared at the end of the previous completed lap, granting Jeffrey Buis a narrow win over fellow Kawasaki rider Inigo Iglesias.
The WSBK race was due to start at 2pm local time, roughly 50 minutes after the WSSP300 race was red-flagged.
But the start was delayed due to “track safety conditions’” before the championship announced at 1:48pm that the race has been cancelled altogether.
In a short statement, the WSBK noted that “Following an incident in #WorldSSP300 Race 1 involving #25 Dean Berta Vinales, the remaining on-track activity on Saturday has been cancelled.”
Apart from WSBK, the opening World Supersport race of the weekend was also scheduled on Saturday afternoon.
Sixteen-year-old Vinales is the cousin of nine-time MotoGP race winner Maverick and has been contesting his rookie season in WSSP300 for the family-run Vinales Racing Team aboard a Yamaha R3.
The championship is yet to provide a update on his condition.
Yamaha’s Toprak Razgatlioglu was due to start Race 1 from pole position after edging out the Kawasakis of Alex Lowes and Jonathan Rea in qualifying.