Senad Lulic scored a far-post tap-in with just 19 minutes of normal time remaining, as Vladimir Petkovic's men secured a place in next season's Europa League
Senad Lulic grabbed the only goal of a horribly underwhelming game, slotting home with just 19 minutes remaining to spark wild celebrations in one half of the capital.
Both sides had played their part in a predictably frenetic opening to the game that resulted in early bookings for both Cristian Ledesma and Federico Balzaretti.
Lazio could have been ahead inside the opening four minutes but Miroslav Klose fired into the side netting after Bogdan Lobont had been unable to hold onto a low strike from the dynamic Lulic.
However, Roma really should have taken the lead soon after when Erik Lamela and Marquinhos combined to put Michael Bradley in on goal, only to see the American's subsequent strike trickle wide.
For the majority of the half, the Giallorossi looked the side most likely to make the breakthrough but, for the most part, they were restricted to long-range efforts from Francesco Totti and Lamela.
In the end, they were lucky to go in level at the break, with Klose surprisingly heading straight at Lobont, after being picked out at the back post by Stefan Radu's deep cross from the left-hand side.
Moments later, the Germany international became the fifth player to enter the book, which merely underlined the fractious nature of a first half that ended just second after Mattia Destro had got his first sight of goal, the striker just failing to climb high enough to get a clean connection on a brilliant cross from Marquinhos.
The latter played his part in a bright spell for Roma just after the break but they just could not get in behind a Lazio defence that, in theory, should have been more vulnerable following the injury-enforced withdrawal of Ledesma on 54 minutes.
Still, the Giallorossi continued to press and Totti tested Federico Marchetti with a decent low strike before the Lazio goalkeeper was called upon again to get down low to stop a snap-shot from Destro.
A goal was coming - but it arrived at the other end, with Lulic tapping home at the back post after Lobont had deflected Antonio Candreva's cross into his path.
Roma tried to rally and very nearly levelled in fortuitous fashion just seconds after the restart when Marchetti lost the flight of a Totti free in the air and ended up desperately pushing the ball up onto the crossbar before luckily gatherin the rebound.
Thereafter, though, it was Lazio who looked the more likely to score, with Lobont denying Stefano Mauri in an injury-time one-on-one. In the end, though, Lulic's goal proved sufficient to earn the Biancocelesti their first meaningful piece of silverware since lifting the same trophy four years ago.