Kostyuk reported she did not consider withdrawing from the clay-court major after receiving news of the attacks.
“Not this morning, because everyone is healthy, alive, and never [needed to go] in the hospital,” she reported.
“But there were obviously times in the match when I would go back to thinking about it.”
Kostyuk, one of Ukraine’s most prominent players, has frequently spoken out against the Russian invasion, external since it began in February 2022.
Kostyuk did not acknowledge Selekhmeteva, who was playing her first match under the Spanish flag after switching allegiance earlier this week.
Ukrainian players have a long-standing policy of not shaking hands with opponents from Russia and its ally Belarus.
Kostyuk was cheered by the crowd during her on-court interview as she told them: “I have been crying this morning. I don’t want to talk about myself today.
“All my heart and all my thoughts go to the people of Ukraine today.”
The 15th seed later added: “I think [the damage] was the closest that it has ever been to my house, and this what probably makes it the most emotional.
“There are better days, worse days, but this one was in the top three worst days, for sure.”
Madrid Open champion Kostyuk is one of the contenders for the Roland Garros title, having won all 12 of her matches on the clay this year.
Kostyuk, whose best French Open result was reaching the fourth round in 2021, will face Katie Volynets next after the American beat France’s Clara Burel 6-3 6-1.