Game Hero: Mantas Kalnietis collected 17 points, seven rebounds and five assists while making eight-of-12 shots from the field to spearhead the Lithuanians.
Stats Don't Lie: Lithuania shot 54.5% from the field while out-rebounding Italy 38-to-25 and holding the Italians to just 44.6% from the field.
Lithuania booked the final spot in the EuroBasket 2013 semi-finals by knocking off Italy 81-77 to set up a final four showdown with Croatia.
Lithuania also secured a spot in the 2014 FIBA Basketball World Cup with the win and automatic qualification to EuroBasket 2015 in Ukraine.
Italy will play Ukraine in the 5-8 Classification Round.
Mantas Kalnietis and Renaldas Seibutis paced the Lithuanians with 17 points each while Jonas Maciulis tallied 13 points to help Lietuva return to a EuroBasket semi-final for the first time since taking bronze in 2007.
"We're very happy to beat such a great team. A little pressure is off. We finally passed the quarter-finals. The key was the fourth quarter," said Martynas Pocius, who scored 11 points for the Baltic side.
"It was a difficult game for us. I cannot say that someone controlled the game. In the end, we found where we are strong, used those positions and we won," said Lithuania coach Jonas Kazlauskas.
Marco Belinelli led Italy with 22 points and Alessandro Gentile scored 15 points. But they were not enough.
"I am very proud of my players. They played a very good basketball game. They left everything on the court," said Italy coach Simone Pianigiani.
Darjus Lavrinovic started strong for Lithuania with five points from inside and outside as well as good rebounding in helping Lithuania build a 9-2 lead. Maciulis also displayed his inside-outside game as Lietuva extended that advantage to 22-12 late in the first quarter.
Gentile came off the bench to nail a triple to pull the Italians within 22-15 after one quarter.
After not recording an assist or scoring in the last group stage game against Spain, Travis Diener scored the opening basket of the second quarter and then nailed a triple as Italy worked their way back into the game, down 27-24.
Seibutis pushed the lead back to 36-28, but Belinelli and Andrea Cinciarini combined for Italy's next 11 points in an 11-4 surge to pull within 40-39 at the break.
Datome gave Italy their first lead with the first basket of the second half but Lithuania responded with a 10-3 run for a 50-44 advantage. Italy were not fazed and punched right back with a 12-3 spurt thanks to six points from Cinciarini for a 56-53 Italy lead. Lithuania briefly reclaimed the lead but Belinelli's driving dunk had Italia up 58-57 after three quarters.
Italy's offence failed to execute early on in the fourth against Lithuania's tough defence as Lithuania went on a 15-0 run in the first six minutes of the fourth for a 72-58 lead. Italy finally got on the board with two Belinelli foul shots and refused to go down without a fight with six straight points to make it 72-64.
Four straight points for Lithuania pushed the margin back to 12 but Belinelli nailed a triple and Gentile hit three foul shots to pull within 76-70. Down the stretch, Lithuania hit enough free throws to stay clear of Italy, who missed a layup with 17 seconds to play that would have cut the deficit to 78-74.