GARRYOWEN 3 ST. MARY'S COLLEGE 6, Dooradoyle
Scorers: Garryowen: Pen: Gerry Hurley
St. Mary's College: Pen: Gavin Dunne; Drop: Gavin Dunne
Full-back Gavin Dunne, who has impressed since his transfer from UCC in the summer, fired unbeaten St. Mary's ahead with a penalty after eight minutes.
The three-point victory also saw them lift the Shay Deering Memorial trophy afterwards, which is competed for whenever the two clubs meet.
Blackrock, Mary's and Dolphin, the three sides left with 100% records in the top division, have opened up a six-point gap on the chasing pack.