Back row Colm McMahon, Shannon's captain for the season, scored a try on his first start since breaking the fourth metatarsal bone in his right foot in October.

Ireland Under-21 hooker Sean Cronin also touched down in the second half to help Mick Galwey's men up back up to first - just a single point clear of Limerick rivals Garryowen.

Blackrock, walloped by Cork Constitution (49-0) and Lansdowne (71-15) in recent weeks, proved sticky opponents and were unfortunate to be left trailing 5-3 at the break.

'Rock fly half Killian McGowan landed a 21st-minute penalty, but McMahon, just five minutes later, made the breakthrough for the home side, scoring his try in the left corner.

Dave Delaney swept the conversion wide and a rather listless first half was closed out with a yellow card for the visitors' prop Garrett Fitzgerald for persistent infringing.

Ten minutes into the second half, Brian Tuohy did well to stave off a certain try from 'Rock scrum half Ross Molloy who broke off the back of a ruck.

Blackrock did get their try on 54 minutes when prop Sean Byrne ploughed over after an Eddie Manawaiti break.

Shannon number 10 Delaney squared it up at eight-apiece on 63 minutes and Cronin's try, five minutes later, proved to be the final act.

Scorers: Shannon: Tries: Colm McMahon, Sean Cronin; Pen: Dave Delaney

Blackrock: Try: Sean Byrne; Pen: Killian McGowan