The Irish province hosted Aironi in re-match of the celtic league battle between the two sides back in September and came out on top with a bonus point victory at Ravenhill on Friday night.
Andrew Trimble crossed for the only try of the first period, with Ian Humphreys, Simon Danielli and Ruan Pienaar touching down on 45, 61 and 68 minutes respectively.
The 1999 European Champions ran out 30-6 victors in Pool 4, although the performance was less convincing than the scoreline suggests.
Glasgow 21-13 Dragons
Glasgow came out on top as two Magners League sides faced each other in the opening weekend of European rugby.
The Dragons travelled to Firhill looking to replicate their recent league win over the Scottish side, but Glasgow had the upper hand taking a 21-13 victory and out scoring the Dragons two tries to one.
Graeme Morrison and Fergus Thomson scored the tries for Glasgow, Adam Hughes scored the Dragons only try on his European.
The Scottish side will look to continue their good start when they travel to face double European champions London Wasps next weekend, while the Dragons must regroup for the visit of the Heineken Cup Champions Toulouse to Rodney Parade.
Leinster 38-22 Racing Metro 92
Leinster produced an impressive bonus-point display, beating current Top 14 leaders Racing Metro 92 at the RDS.
The 2009 European Champions scored five tries in total as they finished comfortable 38-22 winners in the Irish capital.
Leinster led 21-6 at the break thanks to tries from Heineken Man of the Match Sean O'Brien and full back Rob Kearney.
Scores from Richardt Strauss and Jamie Heaslip secured the bonus point with 17 minutes remaining, before Fergus McFadden added even further gloss with a fine last-minute effort.
Impressive centre Albert Vuli-Vuli claimed Racing's first ever Heineken Cup try, while Jerome Fillol and Francois Steyn shared 17 points with the boot.
Toulon 19-14 Ospreys
The Ospreys suffered a late defeat in France with Jonny Wilkinson and Paul Sackey combining to give the hosts a vital opening victory.
Shane Williams looked to have given the Welsh region a famous win in the South of France with an opportunist try on the hour mark before England winger Sackey scored with just four minutes remaining.
Dan Biggar kicked the Ospreys ahead with an early penalty, but missed a drop goal and a further penalty to extend the visitors' lead.
Wilkinson kicked two penalties for Toulon before Biggar struck his second to level the scores at the half time.
Jerry Collins was penalised directly from the re-start and Wilkinson restored his side's advantage from in front of the posts.
Williams had spotted a huge gap at the side of the ruck and stepped inside Rory Lamont to touch down. Biggar missed the conversion and then Wilkinson reduced the lead to two points with a touchline penalty in the 74th minute.
Benetton Treviso 29-34 Leicester Tigers
Treviso have had a fantastic start to the Magners League and came three minutes away from beating double European Champions Leicester Tigers at Stadio Monigo.
Alessana Tuilagi's late score was the difference in Italy after the home side looked to have won the game after a brace of tries from young centre Tommaso Benvenuti and 19 points from the boot of Kristopher Burton.
Leicester's earlier tries came from Matt Smith, Craig Newby, Martin Castrogiovanni and Ben Youngs.
Scarlets 43-34 Perpignan
Stephen Jones scored 28 points, including one of his side's four tries as the Scarlets beat French giants Perpignan in a nine try spectacular at Parc y Scarlets.
Perpignan clawed their way back from 40-15 down after 50 minutes to claim a try bonus point for themselves.
The visitors scored the opening two tries through Jean-Philippe Grandclaude and Julien Candelon to give them a 12-6 lead.
Rhys Priestland crossed twice in quick succession as the Scarlets seized this Heineken Cup tie by the scruff of the neck with a four-try blitz in the space of 15 minutes either side of half-time. Jones and Regan King grabbing the other tries.
Perpignan outscored their hosts on the try scoring front and scored three second half tries through Adrien Plante, Ovidiu Tonita and Damien Chouly.
Cardiff Blues 18-17 Edinburgh
In a repeat of the opening Magners League weekend, Edinburgh travelled to South Wales to face the Blues and once again it was the hosts who were victorious.
It was a tight encounter at the Cardiff City Stadium with Casey Laulala scoring the decisive try ten minutes from time.
Dan Parks was off form with the boot, missing chance after chance to give his side an early advantage.
Chris Paterson scored the first points of the game with a penalty for Edinburgh after four minutes and then Allan Jacobsen crossed for a converted try to give the visitors and 10-0 lead.
The Blues hit back with two Parks penalties as well as a Chris Czekaj try which was also converted by the Scottish fly-half to give them a 13-10 lead.
Laulala then struck to extend the home side's lead and Ben Cairns late try earned Edinburgh a valuable losing bonus point.
London Irish 23-17 Munster
Munster came away with a vital losing bonus point thanks to a last minute Sam Tuitupou try.
Up until the moment the All Blacks centre latched onto Ronan O'Gara's clever grub kick through the last remnants of the home defence it looked as though the two-times champions would leave the Madejski Stadium with nothing.
London Irish were full value for their 15-6 interval lead and had dictated the course of events with their hard-core defence and clever game management from outside half Ryan Lamb, who kicked fifteen points for the home side.
Topsy Ojo stepped in off his wing to intercept a pass from Munster full back Johne Murphy he sped 55 metres to score, just 34 seconds into the second half.
Munster started to get a foothold in the game as their set piece improved and O'Gara added a forth penalty after 68 minutes.
Delon Armitage kicked a long-range penalty from two metres inside his own half after O'Gara's final penalty.
Tuitupou's late try could be vital when the final places in Pool 3 are determined in January.
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