Ukrainian tennis player Marta Kostyuk was booed after refusing to shake hands with her Belarusian opponent at the Roland Garros tournament in Paris on Sunday.

The tensions stemming from Russia’s invasion of Ukraine took center stage in the international tennis championship as Kostyuk faced the Belarusian Aryna Sabalenka, who is the number two in the women’s tennis ranking and one of the favorites for the final victory, in the first round.

The 20-year-old Kostyuk previously criticized the decision by tennis authorities to allow Russian and Belarusian players to compete as neutrals after the start of the conflict in Ukraine, and has refused to shake hands with her Russian and Belarusian opponents since.

The crowd in Paris booed the Ukrainian tennis player on Sunday after she walked away from Sabalenka at the end of the match.

Sabalenka was cheered by supporters as she took a bow at the end of the game. The Belarusian player told reporters that she understands her opponents’ decision not to shake hands.

“I imagine if they’re going to shake hands with Russians and Belarusians, then they’re gonna get so many messages from their home countries,” Sabalenka said after the game.

“If she hates me, OK. I can’t do anything about that,” she added.