The other Group F action saw Russia beat previously undefeated Spain and France cruised past Serbia.
Belarus romped to a 66-51 triumph over the Italians with Yelena Leuchanka pouring in 18 points and grabbing 10 rebounds.
Italy, with a partisan crowd behind them in Ortona, pressured the Belarus jump shooters in the first two quarters but opposing coach Anatoli Buyalski had a game plan and his players executed it to perfection.
Belarus always looked to make the extra pass and constantly got the ball inside to Leuchanka and Anastasiya Veremeenko, and it paid dividends in the second quarter when they scored 14 of their team’s 19 points.
Meanwhile, Italy often punished opponents in this competition with their long-range shooting, but they simply could not get into a rhythm against Belarus.
Raffaella Masciadri and Laura Macchi were a combined zero for 12 from behind the arc, with only Francesca Modica having any success.
She connected on all three attempts from three-point range in the first half and finished four of six (66.7%) from long range.
As a team, Italy were a nightmarish four of 26 (15.4%) from behind the arc.
When they put the ball on the floor and drove to the basket, Leuchanko and host of Belarus defenders were always there to stop them.
“They had the crowd but we played really well on defense,” said Belarus forward Svetlana Volnaya.
“We played a little bit smarter on offense. We settled down. And they played a little more rushed and took quick shots."
Belarus play Group E winners the Czech Republic, winners of the EuroBasket Women two years ago in Turkey, in the last eight.
Russia scored a convincing 64-49 victory over Spain to clinch first place in Group F.
Maria Stepanova collected 19 points, 12 rebounds and three assists and Irina Osipova added 13, eight and two for the Russians.
By coming in first place, Russia earned the right to take on Lithuania in the quarter-finals while Spain must now take on Belgium.
France were too powerful on both offense and defense against Serbia and claimed a 68-60 triumph.
Sandrine Gruda scored 16 points and Emilie Gomis added 14 off the bench for the French, who finished 3-2 for third place in Group F, setting up a final eight showdown with Latvia.
Jacques Commeres, the excellent French coach, looked ahead to the meeting with the Latvians.
"It’s a very good team," he said. "Their position in the other group was second behind the Czechs which is very good. They very dangerous and maybe they play with confidence."
French star Sandra Le Drean knows there should be no easy games when it comes to quarter-final showdowns.
"I think they (Latvia) are a very good team," she said. "We played against them during our camp, but it’s not always the same.
"It’s a quarter-final, a little stressful for everyone, but if we play defense as we did tonight (against Serbia) and before, I think we can win.
"We have to be careful of everybody in that team because everyone can be dangerous."