St. Mary's, who throttled Shannon 53-0 back in Dublin in October, hit the third in the third minute when lock Ciaran Ruddock got in for a try which Gavin Dunne converted.

That score served as a wake-up call for Shannon as memories of the two soft second half tries they conceded against Garryowen looked like coming back to haunt them.

17 minutes were on the clock when young out-half Gareth Quinn McDonogh opened Shannon's account from a penalty. The Ireland Under-20 international started in place of the injured Tadhg Bennett.

The opening try came Shannon's way three minutes before half-time. Winger Luke O'Dea touched down after a series of assaults on the visitors' try-line looked like yielding nothing. Quinn McDonigh added the conversion and in injury-time, the home side struck again. In the build-up to the try there were nine phases of play before number 8 and captain David Quinlan dotted down for his third score of the campaign.

17-7 in arrears, St. Mary's had their tighthead prop Colm McMahon sent to the sin-bin in the 51st minute and Quinn McDonogh landed the resulting penalty.

The visitors, who remain third in the table despite this defeat, kept battling away. Full-back Dunne kicked a penalty and lock Damien Hall garnered a losing bonus point with a try five minutes from the end.

Scorers:

Shannon: Tries: David Quinlan, Luke O’Dea; Cons: Gareth Quinn McDonogh 2; Pens: Gareth Quinn McDonogh 2

St. Mary’s College: Tries: Ciaran Ruddock, Damian Hall; Con: Gavin Dunne; Pen: Gavin Dunne

HT: Shannon 17 St. Mary’s College 7