Traditionalists, diehards and ostriches alike will have a hard job knocking the semi-final format after Saturday's memorable first instalment of the AIL play-offs at Thomond Park. How could anybody not want this?

It may be manufactured and contrived, but it's a helluva lot better than nothing, which is the alternative, and this game was better than anything from the `league' stage. Besides, any new challenge only seems to bring out the best in Shannon.

With the additional challenge of a semi-final came a beefed up effort from St Mary's. Led with characteristic gusto from the front by the omnipresent Steve Jameson, possibly playing his 81st and last AIL game, the St Mary's pack met their Shannon counterparts head on.

They threw themselves into the physical confrontation, stopping home drives in their tracks and often turning the ball over. The miners on the coalface, Barry `Bomber' Browne, and the props Emmet Byrne and Peter Coyle, were as committed as anyone. They gave not an inch in the scrums and exploded the myth about the St Mary's tight five lacking bottle.

It would be hard to quibble with any of the St Mary's pack. Trevor Brennan was as brave as any of them, flinging himself into all-enveloping tackles. Admittedly Brennan's yardage haul was about minus five; his high body positioning making him a tasty target for Eddie Halvey (who says this fellow can't put in the hits?), Alan Quinlan and Co. They were queuing up for him, which perhaps afforded Victor Costello more space to rumble.

Behind the pack, Conor McGuinness quickly plundered his second AIL try for the club, a week after scoring his first, and directed operations with his clever line kicking. Even into a stiff breeze, his up-and-unders were measured to perfection about an inch or two inside the line.

Nevertheless, twice Anthony Foley was there to gather the ball and twice John McWeeney, of all people, failed to put him into touch. This proved costly, as Foley was thus able to begin and finish the thrust for his team's important first-half try.

Yet, despite being given first use of a strong wind, Shannon were rattled, no doubt about it. This was no flashy, all-singing, all-dancing performance from the visitors. For heaven's sake, they were taking Shannon on up front, the deserving Mark Reilly burrowing over from a Jameson take as they opted for a line-out rather than a kick at goal.

Trailing into wind, Shannon were shaken but also stirred. "We had to tighten things up. In fairness to their pack, they took us into the breeze and did extremely well," admitted Shannon coach Pat Murray. "We sat down at half-time and had a look at ourselves and identified certain players who hadn't been playing to their potential. Really it was up to the pack to decide who was going to win the match."

If Foley and Halvey had been the enduringly effective big men up front, then it was Quinlan who set the tone and upped the ante with a dynamic second-half display. Thomond throbbed as the rejuvenated flanker punched holes through the blue ranks with a sequence of ball-in-hand drives. Cue to John Hayes, Mark McDermott and the rest.

Shannon just kept coming at St Mary's in waves, cut down the error count and dominated territorially. In mitigation, the visitors didn't buckle. The tackling around the fringes of all the forwards and especially centres Gareth Gannon and Ray McIlreavy was immense. Shannon couldn't put them away but while Fitzpatrick eventually atoned for a missed 25-yarder from in front of the posts, Thompson hauled 23 points with a perfect eight.

When the pressure cranked up, St Mary's started to crack. Errors punctuated their game. There was a botched Costello-McGuinness move off the base of a scrum, needless concession of penalties and, not for the first time this season, all was compounded by a loss of direction behind the pack.

Fitzpatrick and the quartet of internationals were all culpable, affording Shannon their line-out platform to keep going forward by persistently kicking to touch rather than down the length of the field. Denis Hickie, an immense disappointment on the day, twice missed penalties to touch and then waved the rampaging Quinlan through on the counter. Thus, St Mary's missed touch on the two occasions they should have, and kept finding touch when they shouldn't have.

The coach Steve Hennessy lamented all this and more, and wondered whether McGuinness's foot injury undermined his performance, "but certainly there was a lot of wrong option taking. We didn't put the ball behind their back three like we said we'd do. Crazy. We played into their hands.

"We didn't play from 1 to 15 like we can, like we should, like we promised we would and ultimately that cost us. But in fairness, they deserved to win. I take my hat off to them," added Hennessy, his words drowned out by There Is An Isle from the home dressing-room.

This sense of disbelief and mystification over the tactics employed by some of the St Mary's backs clearly extended to some of the forwards. A speechless Browne, his face battered and scarred, just shook his head. He looked angry and you could understand why.

Long after the final whistle, many of the St Mary's players sat in their hushed dressing-room, still in their gear and faces pointed to the floor.

A bitterly disappointed Jameson spoke through clenched teeth. "I wanted to see their back three being turned in the second half, and I didn't see it." Amazingly, not once.

Ultimately though, this was more about what Shannon did. They dug deeper and, collectively, wanted it more. They played it cute, and they didn't panic. It was ever thus.

Scoring sequence: 4 mins: McGuinness try, Fitzpatrick conversion, 0-7; 8: Thompson penalty, 3-7; 16: Fitzpatrick penalty, 3-10; 18: Foley try, Thompson conversion, 10-10; 23: Fitzpatrick penalty 10-13; 25: Thompson penalty, 1313; 27: Reilly try, 13-18; 35: Thompson penalty, 16-18; 45: Thompson penalty, 19-18; 54: Thompson penalty, 22-18; 58: Thompson penalty, 25-18; 64: Fitzpatrick penalty 25-21; 77: Thompson penalty, 28-21.

Shannon: Jason Hayes; J Lacey, P McMahon, R Ellison, A Thompson; J Galvin, F McNamara; M Horan, J McDermott, John Hayes, K Keane, M Galwey, A Quinlan, A Foley (capt), E Halvey. Replacement: C McMahon for Keane (49 mins).

St Mary's College: K Nowlan; J McWeeney, R McIlreavy, G Gannon, D Hickie; C Fitzpatrick, C McGuinness; E Byrne, B Browne, P Coyle, S Jameson, F Fitzpatrick, T Brennan, V Costello, M Reilly.

Referee: B Stirling (Ulster).