Ukraine's Marta Kostyuk refused to shake hands with Anastasia Potapova after she was beaten by the Russian at the Miami Open.
Their two countries are at war after Russia invaded Ukraine last year.
Potapova, who was recently warned after wearing a Spartak Moscow football shirt at a match, won the second-round encounter 6-1 6-3.
Kostyuk has previously refused to shake hands with Russia's Varvara Gracheva and Belarusian Victoria Azarenka.
Belarus has been a key ally of Russia in the war against Ukraine.
After losing to world number 26 Potapova, Kostyuk said there had been no response from the WTA about a request from Ukrainian players to meet.
Their two countries are at war after Russia invaded Ukraine last year.
Potapova, who was recently warned after wearing a Spartak Moscow football shirt at a match, won the second-round encounter 6-1 6-3.
Kostyuk has previously refused to shake hands with Russia's Varvara Gracheva and Belarusian Victoria Azarenka.
Belarus has been a key ally of Russia in the war against Ukraine.
After losing to world number 26 Potapova, Kostyuk said there had been no response from the WTA about a request from Ukrainian players to meet.