Greece gets on the board first in Perth with Despina Papamichail triumphing 3-6, 6-4, 6-1 over Isabella Shinikova.
Shinikova struggled badly after the first set with wrist and quad injuries.
Papamichael finished the match with 17 winners and 32 unforced errors, while Shinikova, a player who is now ranked No.381 in the WTA tour had 22 winners and 48 unforced errors.
The Greek player, who finished the season at No.158 in the world rankings and reached as high as No.143 last October, made an ideal start to the 2023 season and gave Greece a significant advantage in the tie with Bulgaria
Isabella Shinikova of Bulgaria received medical attention during the United Cup clash but was no match for Despina Papamichail.
Stefanos Tsitsipas is up next against Grigor Dimitrov.
