The Polish world No. 1 overpowered the 26-year-old Croatian qualifier 6-3, 3-6, 6-0 in the championship match.
She picked up her eighth title of the year.
The Polish player earlier this month lost the final of the Ostrava Open tennis tournament in the Czech Republic to home favourite Barbora Krejčíková.
Świątek last month won the US Open, capturing her third Grand Slam trophy.
The 21-year-old, coached by countryman Tomasz Wiktorowski, in early April took over as the new number one in women's tennis, becoming the first Pole to top the world rankings.
(gs)
Source: IAR, PAP