Leinster fought back from a lacklustre first half to beat Aironi in Saturday's Pro 12 clash at the RDS.
Isa Nacewa missed three penalty chances to put Leinster ahead before Nick Williams' 35th-minute try helped Aironi take a surprise 7-0 lead.
However, impressive fly-half replacement Ian Madigan notched a try on 48 minutes which Nacewa converted.
Nacewa, Luke Fitzgerald and Rhys Ruddock scored further tries as Leinster ran out comfortable winners.
Half-time replacement Madigan sparked Leinster into life and was instrumental in their four second-half tries.
In a game played in wet conditions, Aironi produced early pressure but poor handling saw them wasting three promising positions in the Leinster 22.
Nacewa had the first of his three first-half missed penalties in the 16th minute and David Kearney, Fionn Carr and Luke Fitzgerald also failed to take advantage of attacking opportunities in the opening period.
Aironi held out despite having winger Sinoti Sinoti sin-binned in the 23rd minute and the Italians then went ahead when former Munster player Williams touched down after an attacking drive following a line-out.
With Tito Telbaldi adding the conversion, Aironi led 7-0 at the break but Leinster were on terms by the 48th minute as Madigan, on for debutant Noel Reid at half-time, scored the home team's first try.
Madigan had turned down a penalty chance, instead opting to kick for the corner, and good line-out ball was finished off by the replacement fly-half's defence-splitting dart.
Nacewa finally landed a kick to level the game and the full-back himself scored Leinster's second try 10 minutes later after another Madigan break.
Fitzgerald's breakaway try made the game safe after he had collected a stray Gilberto Pavan pass on halfway.
Leinster chased the bonus point in the closing stages and it was secured in injury-time as Ruddock pounced following a five-metre scrum.
Leinster: I Nacewa, F Carr, E O'Malley, L Fitzgerald, D Kearney, N Reid, C Willis, H van der Merwe, R Strauss, J Hagan, S Sykes, D Toner, C Ruddock, R Ruddock (cpt), L Auva'a.
Replacements: I Madigan for Reid half-time, J Murphy for C Ruddock 50, D Browne for Sykes 59.
Not used: J Harris-Wright, J McGrath, J O'Connell, J Cooney, B Macken.
Aironi: R Trevisan, S Sinoti, R Quartaroli, G Pizarro, G Venditti; T Tebaldi, T Keats; N Williams, S Favaro, J Sole; G Biagi, J Furno; F Staibano, R Santamaria (cpt), A De Marchi.
Replacements: M Aguero for Alberto de Marchi 59, N Olivier for Keats 59, G Pavan for G Pizarro 59, L Redolfini for Staibano 67, F Cazzola for Biaga 77.
Not used: D Giazzon, F Ferrarini, G Bronzini.