The match finished 1-1 after Lazio's slender lead, which was earned by Mauro Zarate only on four minutes, was cancelled out by a Giampaolo Pazzini strike two minutes after the half-hour mark.
The hosts, who also won the title in 1958, 1998, 2000 and 2004, eventually snatched the trophy after winning the shoot-out.
Argentine ace Zarate opened the scoring in a superb fashion after feinting past Hugo Campagnaro to slot home with a curling a right-footed shot from the edge of the penalty area.
Afterwards, the match was an evenly-balanced affair, with both teams trying to carve out scoring opportunities.
Pazzini hit the equalizer with a looping header, following spectacular efforts by Antonio Cassano and Marius Stankevicius.
The visitors could have ended the game in normal time when Cassano almost hit a screamer, but his effort was cleared off the line by Stephan Lichtsteiner.
There was more action in extra-time, as both sides tried to pile up pressure upfront to net a precious stunner, but to no avail.
Lazio goalie Fernando Muslera played a major role by blocking Campagnaro's shot, before Ousmane Dabo scored the winner.