Cork Constitution 33 St Mary's 21
An injury time try by Joey Sheahan helped Cork Con to a bonus point at Temple Hill and sent the Dubliners home with nothing.
The Cork side led 13-9 at the break following a Mick O’Driscoll try, converted by Pat McCarthy, who also kicked two penalties.
Barry Lynn kept St Mary’s in the hunt with three penalties into the strong wind.
They took the lead with a David Claire try, converted by Lynn, only for the Cons to hit back immediately with a try from man of the match McCarthy.
Ultan O’Callaghan scored the third before James Norton crossed for the visitors and McCarthy then kicked a penalty.