Olexandra Gorbunova, who led Division A in scoring last year at 20.9 points per game, poured in 22 and also corralled 11 rebounds as Ukraine won the Group A clash, 81-76.
Iryna Biryuk contributed 16 points and Ol'ga Dubrovina 10 for the winners, who are coached by Volodymyr Bryukhovetskiy.
Noel Monik Kuin scored 19 and Gergana Branzova-Erdenay 18 for Bulgaria.
Ukraine narrowly missed out on direct qualification for the EuroBasket Women with five wins and three defeats while the Bulgarians were 2-4.
When Zornitza Kostova drilled a jump shot to put the hosts into a 36-24 lead in the second quarter, they looked to be in trouble.
At half-time, Gergana Slavcheva had 15 points for Bulgaria who were still on top at 45-38 and another three-ball from Kostova early in the second half stretched the home side's lead to 52-42.
Ukraine made their move midway through the third quarter.
Behind 56-48 after a Kuin free throw, Tetyana Shchypakina made two at the charity stripe for Ukraine and followed that up with a three-pointer to spark the visitors into life.
Bryukhovetskiy's team went on to outscore Bulgaria 19-3 over the final 4:40 of the period for a 67-59 advantage and they stayed in front for the entire fourth quarter.
Ukraine outrebounded Bulgaria 42-34.
Lyubov Alyoshkina and Olena Zherzherunova each finished with nine points and nine rebounds for the winners.