Fifth-seed Jovanovski, ranked 97 in the world, claimed a 6-3 6-1 success on the first final appearance of her career.
The Belgrade-born 20-year-old found Cohen a stubborn foe, but was the dominant force in the crucial points.
After an early exchange of breaks, Jovanovski edged into a 4-2 lead before clinching the opening set after 48 minutes.
The Serbian right-hander then raced into a 4-0 lead in the second and wrapped up the contest after just over an hour and a half.
Jovanovski told the tournament's official website: "I've worked really hard for this.
"I had two weeks really hard preparation before this tournament so I was expecting to play good here.
"I went to the match having nothing to lose.
"I was so positive and was just trying to fight for every point and not think about win or lose, just to play the point the best I can."