Leinster virtually assured their place in the Magners League play-offs with a 20-8 victory over Aironi at the Stadio Zaffanella.
Tries by number eight Sean O'Brien and prop Cian Healy now means they lie in second, seven points ahead of the Ospreys having played a game more.
However, they will have been disappointed not to garner the try bonus-point. But to Aironi's credit, they defended stoutly and deserved the score given to them by flanker Gareth Krause.
Winger Fergus McFadden missed an early opportunity to open the scoring but made up for the error soon after by converting his second penalty attempt.
Scrum-half Tito Tebaldi had the chance to level the game but his effort drifted wide. Looking to secure the expected four-try bonus-point which would have significantly aided their home play-off aspirations, Leinster opened their account on 20 minutes when powerful back-rower O'Brien went over.
McFadden added the extra two points and then scored another penalty to leave Leinster in control at 13-3. A Healy try just before half-time, converted by McFadden, confirmed their dominance. Leinster's task looked to have become even easier when number eight Nick Williams was sin-binned for Aironi.
However, the Irish side perhaps became complacent as it was hosts who looked more threatening while Williams was off the field. And with 13 minutes to go, Krause brought the Italian side right back into contention.
Fly-half James Marshall missed Aironi's third kick at goal and they continued the press as the match entered it's closing stages, but they couldn't break down strong Leinster defence.
Tries: O'Brien, Healy
Cons: McFadden 2
Pens: McFadden 2
Aironi: 15 Horacio San Martin 14 Kaine Robertson 13 Gilberto Pavan 12 Gabriel Pizarro 11 Danwel Demas 10 James Marshall 9 Tito Tebaldi, 8 Nick Williams, 7 Gareth Krause, 6 Josh Sole, 5 Marco Bortolami (c), 4 Joshua Furno, 3 Fabio Staibano, 2 Fabio Ongaro, 1 Alberto de Marchi.
Replacements: 16 Luigi Ferraro, 17 Salvatore Perugini, 18 Luca Redolfini, 19 Quintin Geldenhuys, 20 Nicola Cattina, 21 Pablo Canavosio, 22 Matteo Pratichetti, 23 Riccardo Bocchino.
Leinster: 15 David Kearney, 14 Fergus McFadden, 13 Brian O'Driscoll (c), 12 Eoin O'Malley, 11 Luke Fitzgerald, 10 Ian Madigan, 9 Eoin Reddan, 8 Sean O'Brien, 7 Shane Jennings, 6 Rhys Ruddock, 5 Nathan Hines, 4 Devin Toner, 3 Mike Ross, 2 Jason Harris-Wright, 1 Cian Healy.
Replacements:16 Richardt Strauss, 17 Heinke van der Merwe, 18 Stan Wright, 19 Leo Cullen, 20 Dominic Ryan, 21 Isaac Boss, 22 Jonathan Sexton, 23 Shane Horgan.
Venue: Stadio Zaffanella
Referee: Andrew McMenemy