Sainz had made a poor getaway from fourth, but appeared to have consolidated fifth place as the pack turned into the left-hand apex of the Tamburello chicane.
But Ricciardo, who had been on the Spaniard's inside, understeered into the Ferrari's sidepod and spun Sainz into the gravel, before receiving a secondary hit from behind from Valtteri Bottas's Alfa Romeo.
