Last season’s Ulster Bank League Division 1A finalists Clontarf and Cork Constitution both fell to their second successive defeats of the new campaign on Saturday, losing to Limerick’s Young Munster and Garryowen respectively.
For the visit of champions Clontarf, Young Munster were without Robin Copeland, who has starred for them in recent weeks, but they were able to call on recent PRO12 debutant Dan Goggin who partnered Mark Doyle in the centre with talented teenager Calvin Nash moving to the right wing.
New signing Jack Power, the Ireland Under-20 international, and Sean Long came into the Clontarf back-line, while hooker Rory Litchfield started in the visitors' otherwise unchanged pack.
'Tarf made the stronger start in Greenfields, twice hitting the front through the boot of Rob Keogh and an unconverted try from flanker Karl Moran. A purposeful break from Matt D'Arcy then played in winger Keogh for a 35th-minute converted effort.
Clontarf were proving a match for the energetic home forwards and after a shaky few scrums, the north Dubliners managed to impose parity if not a slight dominance in the set piece.
However, Munsters finished the first half in fine style, scoring two quick-fire tries to nip into a 17-15 lead. They upped the pressure and intensity, knocking a penalty to the corner and Thurles tighthead prop Colm Skehan, so influential in Munster's Junior Interprovincial title win last season, struck from a well-executed maul.
The Cookies' second try came straight from the restart, the north Dubliners leaking possession to a counter-ruck and their defence falling off as Munster Academy recruit Nash waltzed in for full-back David O'Mahony to convert and put two points between the sides.
That was still the gap at the end of an absorbing, defence-dominated second period. 'Tarf dug deep during replacement scrum half Sam Cronin's sin-binning and Keogh's 77th-minute penalty – moved 10 metres closer for dissent from the Cookies – edged the visitors back in front.
'Tarf had done enough to secure the victory but again they erred from the restart, failing to control possession out wide and then coughing up a penalty in front of their posts for holding on. Munsters full-back O'Mahony stepped up to take the kick and seal a rousing 20-18 triumph, moving Gearoid Prendergast's men level with Lansdowne at the top of the table.
Referee: Mark Patton (IRFU)