She won one of the bronze medals in the women's kumite +68 kg event at the 2018 World Karate Championships held in Madrid, Spain.

[1][2] In 2015, Antunovic lost her bronze medal match in the women's kumite +68 kg event at the European Games held in Baku, Azerbaijan.

[3] She also competed in the women's kumite +68 kg at the 2019 European Games held in Minsk, Belarus.

She lost all three matches in the elimination round and she did not advance to compete in the semi-finals.

In 2021, Antunovic competed at the World Olympic Qualification Tournament held in Paris, France hoping to qualify for the 2020 Summer Olympics in Tokyo, Japan.