Young Munster earned their fourth successive win in Division 1A, thanks to a deserved triumph over local rivals in a lively derby clash at Tom Clifford Park.
The home victory, coupled with St. Mary's collapse against Blackrock, means that Munsters are now just two points behind third-placed Mary's in the table.
Out-half Willie Staunton dropped a goal in the sixth minute to the delight of the large home support. A crisply-struck penalty from scrum half Alan Kingsley followed, four minutes later.
Gareth Quinn McDonogh, who came on late in the Ireland Under-20s’ win over Scotland on Friday night, opened Shannon’s account with a penalty on the quarter hour mark.
Kingsley cancelled that score out with his second penalty, in the 28th minute, and the Cookies were 9-3 in front at the break.
Full-back Ray Moloney went straight in under the posts for a converted try in the early stages of the second half and Shannon could find no way back.
Moloney followed up on a great break and kick ahead by Young Munster number 8 Neville Melbourne to score the all-important try. Munsters saw out the win with flanker Shane Hassett making a very good impact off the bench.
Referee: Dudley Phillips (IRFU)