In their desperation St Mary's made desperately heavy weather of it, before getting there in the end when John McWeeney completed a fine hat-trick of tries in the 76th minute. The Templeville Road faithful heaved a huge sigh of relief.
After successive defeats had knocked them off the top of the table, and with a wounded Shannon at their Thomond Park nemesis looming next (though call-ups for McWeeney and Mark McHugh into Ireland's squad for the Hong Kong Sevens jeopardises that fixture) victory was essential. It restores them to first place, albeit on points difference, above Terenure.
It should never have been such a close shave as St Mary's created a hatload of chances, But a welter of referee Bertie Smith's decisions went against them; Clontarf's resistance was stubborn; and St Mary's were over anxious.
The home side had a huge platform in the scrums, where Clontarf could scarcely buy a ball even on their own put-in, while Malcolm O'Kelly gave a masterclass at line-outs and restarts.
St Mary's also set up a torrent of ruck ball but much of it was slowed down or even denied them, primarily by Pat Ward, who seemed to be forever at the bottom of rucks, usually last up and usually on the opposition side of the ball. The cover tackling of Ronan O'Reilly, Ollie Winchester and David O'Brien also prevented tries.
For St Mary's there was also too much battering around the fringes and too many head-down charges at the gain line, be it Ray McIlreavy or big rumblers Victor Costello and Trevor Brennan.
Either side of Richie Murphy kicking Clontarf ahead, Gareth Gannon overcomplicated a big overlap and Daragh McElligott snared Dennis Hickie by the ankles, before Mark McHugh started an off-key day with the boot by missing a straightish penalty - his return would be two from six.
Incessant home pressure finally yielded a tap-over penalty for McHugh and McWeeney's first try, as he was driven over by Alan Conboy (who replaced Peter McKenna after the latter cried off injured). Peter Smyth, who had a fine game, had retrieved Costello's over-cooked pass from Hickie's miss-pass with a clever reverse pass of his own.
However St Mary's struggled to retain ruck ball, where Clontarf eagerly made the most of it. A turnover, coupled with good recycling by Brian Davitt, allowed Murphy to land a snap drop goal.
Murphy then took the ball up the middle following a lineout drive, and when the St Mary's wide backs were penalised for offside O'Reilly quick-wittedly tapped for Alan Reddan to take Hickie's tackle on the outside and reach for the line; Murphy's wounded duck conversion from the touchline went over.
With Smith's curious penchant for penalising the attacking team, St Mary's continued to feel wronged whereas Clontarf were now feeling sprightly and it required a try-saving tackle by McWeeney to deny O'Reilly after he had deftly probed the blindside with Dave Moore and Winchester.
McWeeney's next act in a huge performance was his second try. Again Smyth was heavily involved, leading a big rumble off a lineout on half way. Conboy box kicked off another turnover, Hickie sprinted across the field and Costello unselfishly provided the link for McWeeney.
O'Kelly was then denied a try when Smith harshly decreed a double movement after the lock took McElligott's covering tackle in the corner before Murphy made it 16-13 at the break with another penalty.
Murphy missed a chance to extend the lead four minutes after the interval and as Clontarf generally opted to play the game in their own territory rather than kick it downfield, much to coach Alex Wyllie's annoyance, the outhalf was subbed late on.
Scrum pressure realised an equalising short-range penalty by McHugh, but he scuffed another kickable one as the battering intensified against Herculean defence. As home desperation reached its height, Smyth charged down O'Reilly's box kick (amid a hint of offside) and initiated another big drive. From the recycle McHugh made some hard yards up the middle and offloaded blind in the tackle for the supporting McWeeney to crash over.
SCORING SEQUENCE - 4 mins: Murphy pen 0-3; 18 mins: McHugh pen 3-3; 21 mins: McWeeney try 8-3; 27 mins: Murphy drop goal 8-6; 32 mins: Reddan try, Murphy con 8-13; 36 mins: McWeeney try 13-13; 40 mins: Murphy pen 13-16; 51 mins: McHugh pen 16-16; 76 mins: McWeeney try, Campion con 23-16.
ST MARY'S: A Conboy; D Hickie, R McIlreavy, G Gannon, J McWeeney; M McHugh, A O'Sullivan; P Coyle, P Smyth, D Clare, P Sullivan, M O'Kelly, T Brennan (capt), V Costello, R Doyle. Replacements: F Campion for McIlreavy (53-57 mins, 75 mins), N Foxe for Coyle (67 mins).
CLONTARF: O Winchester; D Rossi, D McElligott, C Bewley, A Reddan; R Murphy, R O'Reilly; W O'Kelly, T Kearns, A Clarke, D Moore, C Power, P Ward, C Brownlie (capt), B Davitt. Replacements: D O'Brien for Rossi (14 mins); D Hyland for O'Kelly (46-54 mins); A Dignam for Davitt (52 mins).
Referee: B Smith (Munster).
