A claustrophobic intensity and a latent desire for revenge, fuelled by the two previous confrontations between these sides, provided the core ingredients of Shannon's performance at Thomond Park on Saturday. For the first time this season, the Limerick club broached the performance levels that have ensured three consecutive All Ireland League crowns.

St Mary's College had the temerity to travel to Limerick with back-to-back victories over Shannon in their pocket: for the hosts, the contest transcended a battle for points, it was about pride as much as taking another measured step towards a fourth crown.

The Dublin club could not have harboured genuine expectations of victory. An insipid, lacklustre defeat by Clontarf nine days ago, injury problems that afflicted the front and second rows and the continued absence of Trevor Brennan and Conor McGuinness hardly augured well for a successful raid on the Shannon citadel.

Any forbodings about the St Mary's pack quickly dissipated as they embraced the task in hand with great gusto. Unfortunately for the visitors, bravery does not always guarantee results. They met a Shannon eight whose superior physical development and ability delivered the desired edge in the scrums and in contact situations.

John Hayes and captain Anthony Foley made huge inroads in carrying possession, the excellent Eddie Halvey and combative, and at times petulant, Alan Quinlan, did so with a little more elan.

Mick Galwey was another willing buttress, who also relished his front-of-the-line-out battle with Steve Jameson, a well-contested duel.

But it was in the scrums that Shannon displayed tactical nous in stymieing the obvious threat of Victor Costello. Marcus Horan and Noel Healy ensured that the scrum slewed so that Costello was forced to take the long route from the base of the scrum, thereby negating his traditional impact.

To his credit, Costello worked purposefully to overcome this handicap and invariably took out two or three tacklers. St Mary's, though, were in no position to avail of this platform: scrum-half Eoin McCormack did not enjoy a productive afternoon, while Mark Reilly and Mark Cuddihy were more effective defensively than in possession.

Compounding obvious problems was an injury to Frank Fitzgerald after 36 minutes. The second row, who had been enjoying a fine match, was forced to retire, with another youngster, Peter Sullivan, joining the fray.

His slender frame highlighted St Mary's' problems in the second row. The fact that loosehead Emmet Byrne and replacement prop Peter Coyle were playing their first senior matches in six and eight weeks, respectively, underlined the visitors plight.

Nevertheless, they played with a resolve that maintained a competitive aspect to the match until the 77th minute. As Shannon coach Pat Murray conceded: "We were losing 6-0, leading by a point at 12-11 and to be honest, it could have gone either way until near the finish when we pulled clear. It was close for a very long time."

Murray, understandably, applauded the work of his pack and also paid tribute to the defensive resilience of centres Rhys Ellison and Paul McMahon. "I thought they were superb against a very good Mary's backline. We decided beforehand to leave a corridor inside Jim Galvin and if St Mary's wanted to cut back, then we would let our backrow deal with them. It meant that we always had numbers to look after their dangerous runners."

The preparation matched the execution with Ellison, in particular, snuffing out the threat posed by the St Mary's three-quarter line with some thunderous tackling.

St Mary's out-half Fergal Campion, playing his first senior game since the corresponding fixture in December 1996, kicked two superb penalties to give the visitors a 6-0 advantage, only for Shannon to wrest control with a combination of error and sustained bouts of continuity inspired by the home pack that forced the concession of penalties.

Andrew Thompson exacted maximum retribution with four superb penalties prior to the interval. St Mary's needed to score first after the re-start and did so within 40 seconds. Costello bounced Healy after Shannon had turned over possession on the visitor's 22. The number eight fed Knowlan, who demonstrated superb hands to put Denis Hickie away.

The international wing, who had only arrived in the dressingroom half and hour before kick-off due to sitting his finals that morning, chipped past Thompson, easily outpaced Jim Galvin to hack on and score. Campion failed to convert.

Shannon stormed back and following a well-worked line-out take and drive, Thompson dived over for a try he failed to convert. A Thompson penalty on 61 minutes was followed on 77 by an excellent try from Ellison, who finished off his own break in a move that worked with trainingground precision.

Thompson converted, but was unable to do again when three minutes into injury time, John Lacey raced 90 metres after intercepting McCormack's sloppy pass. Shannon continue to find the answers: for St Mary's, the overcrowded treatment table ensures more modest aspirations for the coming weeks.