Kostyuk defeated Gracheva 6-3 7-5, collapsing to the court after converting match point, before refusing to shake hands with the Russian.
The 20-year-old, who is from Kyiv, said at January’s Australian Open that she would not shake hands with any Russian or Belarusian opponent with war raging in her country.
She refused to shake hands with Victoria Azarenka of Belarus at the US Open in September last year. Belarus is being used as a key staging ground for Russia’s war in Ukraine.
Kostyuk dedicated her maiden WTA singles title to her native country during the trophy presentation.
“Being in the position that I am in right now, it’s extremely special to win this title,” Kostyuk said.
“And I want to dedicate this title to Ukraine and to all the people that are fighting and dying right now.”
Kostyuk did not acknowledge the beaten finalist in her acceptance speech.
The tournament win, the first for a Ukrainian woman since Elina Svitolina in 2021, elevated Kostyuk to No. 40 in the WTA rankings.
Among the grand slams, only Wimbledon has banned Russian and Belarusian players from competing, leading to a $1 million fine by the men’s tour.
Russian and Belarusian players were allowed to play at the Australian Open this year without their flag or country displayed.