Leinster were forced to overturn a half-time deficit to eventually battle out a 21-16 win over Aironi at the RDS on Thursday.
The Italians led 10-3 at the break but will have to settle for a losing bonus point.
A late David Kearney try finally broke the battling visitors' resistance as Leinster secured an uninspiring home victory.
Nick Williams' 35th-minute try gave the Italians a seven-point half-time advantage and had them dreaming of their first ever Magners League win.
But second-half touchdowns by Niall Morris and Kearney, allied to 11 points from man-of-the-match Isa Nacewa, saw a youthful Leinster grind out the victory.
Bottom side Aironi at least took something from the match, with Paolo Buso's last-minute penalty securing them their first league point earned outside Italy.
Kevin McLaughlin, who started in Leinster's second row, failed to gather the kick-off and Kaine Robertson drew a second-minute penalty which Tito Tebaldi slotted over.
The opening half was less than memorable, with handling errors, crooked line-outs and overcooked kicks blighting general play.
Nacewa popped his second penalty attempt through the posts after an infringement from Fabio Staibano, and Leinster got straight back on the attack.
There was some incisive running from Brendan Macken and Kearney, but a forward pass from Stephen Keogh to Eoin O'Malley curtailed a promising move.
Teenage centre Macken's debut was cruelly ended by a broken collarbone, disrupting Leinster's plans further.
Tebaldi missed two penalties - the first smacking the right hand post - and Ian Madigan began the second quarter with a long range miss.
Aironi's aggressive defence kept Leinster out of scoring range and the Italians enjoyed their best spell before the break. Paul O'Donohoe's loose pass set Aironi off on a breakaway which ended with Horacio San Martin being caught short of the try-line.
The visitors used turnover ball again to pile forward through their pack. Williams, the former Munster back rower, got over the line but television match official Peter Ferguson said the grounding was inconclusive.
A minute later, Williams made certain of the try as he broke off a five-metre scrum, flattened Madigan and crashed over. Tebaldi added the conversion for a seven-point lead.
Leinster's blushes were spared in the final minutes of the opening stanza. Replacement Morris prevented a second try for Aironi, bringing down Jacob Erasmus as the flanker tried to finish an interception in the right corner.
Leinster upped the intensity for the start of the second half and Nacewa's close-in penalty cut the gap to 10-6.
In the 46th minute, there was a powerful burst on the left wing by Richardt Strauss whose one-handed offload invited Morris through and he outpaced Danwel Demas for a neat finish under the posts.
Nacewa's conversion was cancelled out by a terrific drop goal from the influential Buso and it was game on again at 13-13.
Nacewa kicked his third successful penalty to make it 16-13 to the hosts and after Buso curled a penalty effort wide of the uprights, Leinster roared forward.
The 20-year-old Rhys Ruddock, the province's youngest ever captain, led the charge in a side containing eight players aged 23 or under.
One of them, winger Kearney, gathered Shane Jennings' pass out of the tackle and brushed off James Marshall's challenge for the decisive score in the left corner.
Tries: Morris, Kearney
Pens: Nacewa 3
Pens: Tebaldi, Buso
Leinster: 15 Isa Nacewa, 14 Andrew Conway, 13 Brendan Macken, 12 Eoin O'Malley, 11 David Kearney, 10 Ian Madigan, 9 Paul O'Donohoe, 8 Stephen Keogh, 7 Dominic Ryan, 6 Rhys Ruddock (capt), 5 Devin Toner, 4 Kevin McLaughlin, 3 Clint Newland, 2 Richardt Strauss, 1 Heinke van der Merwe.
Replacements: 16 Jason Harris-Wright, 17 Jack McGrath, 18 Simon Shawe, 19 Ed O'Donoghue, 20 Paul Ryan/Shane Jennings, 21 Isaac Boss, 22 Ian McKinley, 23 Niall Morris.
Aironi: 15 Paolo Buso; 14 Kaine Robertson, 13 Gabriel Pizarro, 12 Horacio San Martin, 11 Danwel Demas; 10 James Marshall, 9 Tito Tebaldi; 8 Nick Williams. 7 Jaco Erasmus, 6 Nicola Cattina, 5 Joshua Furno, 4 Marco Bortolami (c), 3 Fabio Staibano, 2 Roberto Santamaria, 1 Alberto De Marchi.
Replacements: 16 Luigi Ferraro, 17 Andrea De Marchi, 18 Luca Redolfini, 19 George Biagi, 20 Andrea Benatti, 21 Pietro Travagli, 22 Alberto Benettin, 23 Matteo Pratichetti.
Venue: RDS, Dublin
Referee: Nigel Owens (Wales)
Assistant referees: David Wilkinson (Ireland), Mark Hermin (Ireland)
Television match official: Peter Ferguson (Ireland)