Substitute Paula Fitzpatrick's second-half try gave Ireland Women a hard-earned 14-3 victory against a battling Italy Women side to rebound from two consecutive losses at Donnybrook.
The Italians began brightly, full-back Manuela Furlan looking sharp in attack and the forwards excellent at the breakdown.
Ireland though, raised their level and struck back through Women's Six Nations debutant Lindsay Peat, the prop bundling over after superb defensive work from Ciara Cooney and a characteristically powerful Sene Naoupu carry.
Fitzpatrick then appeared from the bench to seal victory as she got on the end of a superb Irish maul.
It was Italy Women who started the stronger, dictating play from the outset and setting up camp inside the Irish 22, but they will have been disappointed to emerge with only three points after a Michela Sillari penalty.
Tierney's side shook of the inertia of their slow start and began to work themselves into the game, Alison Miller - on her return from sevens duty - was a rock under the high-ball and consistently threatened on the counter.
Ireland Women began to build pressure, Captain Briggs breaking well in the midfield and it was from a Cooney charge-down after 30 minutes that the breakthrough came.
Cooney was up quickly on Rigoni, and Ireland managed to recycle the ball quickly, Naoupu shrugging off two tacklers before an excellent last-ditch Manuela Furlan tackle denied the centre.
Six Nations debutant Peat was on hand from the ensuing ruck to power over and put Ireland Women ahead. Briggs converted to consolidate the lead at 7-3.
Both Ireland Women and the Italians looked rusty at the beginning of the second-half, with numerous handling errors from both sides.
It was Tierney's side though who began to look the more confident and with Ailis Egan carrying well and Cooney continuing her powerful performance in the engine room, they started to wear down the hosts.
With the women in green piling forward, Italy Women defended stoutly for the most part, but were broken down by a tightly formed Irish maul just past the hour mark.
Replacement Fitzpatrick was the benefactor as the Irish forwards' tight maul bulldozed through the Italian pack and marched over the line. Nora Stapleton added the extras excellently from out wide.
