Kostyuk secured her first senior tournament win at the ATX Open with a 6-3 7-5 victory over Gracheva.
The 20-year-old has been a vocal critic of Russian and Belarusian players being allowed to continue to play on the WTA Tour, and spoken previously of her disapproval of players who refuse to condemn the invasion of her country by Moscow.
After securing victory in Austin, Kostyuk shook the hand of the umpire but not her beaten opponent, twice walking past a beaten Gracheva for a handshake as the Russian headed directly to her chair.
The eighth seed dedicated her victory to “all the people who are fighting and dying” in the conflict.
“Being in the position that I’m in right now, it’s extremely special to win this title,” Kostyuk said. “I want to dedicate this title to Ukraine and to all the people who are fighting and dying right now.”
Kostyuk reached the third round of the Australian Open in January.
Russia escalated the ongoing conflict with Ukraine on 24 February last year by launching a large-scale invasion into the east of the country.
Under WTA rules, players from Russia and Belarus (a close ally of the Vladimir Putin-led goverment) are allowed to compete on the Tour.
However the flags of the two nations do not appear alongside competing individuals.
The Lawn Tennis Association (LTA) and the All England Club (AELTC) are currently weighing whether to allow players from the two countries to play at this summer’s grass events in the United Kingdom.
Russian and Belarusian players were banned from Wimbledon last year, resulting in the stripping of ranking points from the tournament and a fine.
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