Primoz Roglic finished first in Santiago de Compostela, extending his distance down to second-placed Enric Mas, Spain.
The margin of victory is the largest in Vueltan since 1997.
It was Roglic's fourth stage victory in this year's edition.
His fine form thus continues after he also won Olympic gold in the speed race in Tokyo earlier this summer.
The Swede Tobias Ludvigsson finished 99th in the total.