Jamie Arnold led the way for Virtus with 22 points and 11 rebounds as they qualified for the next phase of the competition.
In the first game between the two sides back on November 26, Virtus only beat Oostende 70-69.
Matteo Boniciolli, the coach of Virtus, said: "The difference between the first game against Oostende and this game is that the first game also was one of my first games as coach (of Virtus).
"We have been working hard since then and improving a lot."
Virtus trailed 7-3 early on but opened up an 18-13 lead at the end of the first quarter.
Lionel Bosco's jump shot tied the game at 20-20 early in the second quarter but Virtus found their rhythm and Arnold's three-ball at the end of the second quarter gave them a 46-36 half-time advantage.
Oostende fought bravely and kept the game close.
They closed the gap to three points in the third and finally early in the fourth managed to tie the game at 65-65 on a Bosco three.
Arnold hit a jump shot to put Virtus back in front and they stayed on top for the final 8:22, ultimately winning by 11.
"We knew it was going to be a tough game," Arnold said. "We knew it was going to be war. It feels great to qualify."