Young Munster lost ground in the Ulster Bank League Division 1A title race as their three-match winning run was ended by second-from-bottom St Mary's College who gave themselves a timely lift with a 21-15 triumph at Templeville Road.

Leinster 'A' out-half Cathal Marsh was Mary's lone scorer this afternoon, landing seven penalty efforts as Peter Smyth's men, who led 12-9 at the interval, secured their first win in four league outings.

Third-placed Young Munster scored two first half tries through powerful back rowers Yasin Browne and Sean Rennison, but the visitors' discipline let them down with Marsh nailing four penalties in the closing 40 minutes compared to a single effort from Gearoid Lyons.

Elsewhere, Old Belvedere were the main movers in climbing two places to fifth after Josh Glynn's impressive 17-point tally propelled them a 25-13 victory over UCD at Anglesea Road.

The students made the better start with Leinster 'A' star Ross Byrne splitting the posts from a 25-metre penalty and five minutes later, Byrne's cross-field kick was gathered and dotted down by winger Sam Coghlan-Murray for his third try in two games.

Byrne's outstanding touchline conversion had UCD 10-0 in front, but the dependable Glynn replied off the kicking tee and breaks from Michael Oyuga and captain Jonathan Slattery got the 'Belvo attack firing.

Glynn and Byrne swapped further penalties by the half-hour mark and despite losing hooker to a 31st minute yellow card, the hosts went through the phases to set up recent Leinster cap Steve Crosbie for a drop goal.

That cut the UCD lead to 13-9 for half-time and with the students having flanker Donagh Lawler sin-binned late on, the momentum was shifting in Old Belvedere's favour.

The trusty right boot of winger Glynn converted a penalty, two minutes into the second half, and UCD found themselves trailing for the first time when Glynn landed his fourth successful penalty in the 53rd minute.

Moving into the final quarter, 'Belvo pressed for a try during a long spell of dominance. They fell just short of crossing the whitewash but a further penalty and, after a yellow card for UCD's Jordan Coghlan Glynn made it 18-13.

Bobby Byrne's young side were still in contention until Old Belvedere replacement Aaron Sheehan drove over six minutes from time for a converted try, putting the final outcome beyond doubt.

In what surely must be a league record, Dolphin registered their third successive draw when their bruising clash with hosts Ballynahinch finished level at seven points each at Ballymacarn Park.

Having lost their first four games, the bottom-placed Corkmen have now steadied the ship somewhat by picking up six points from their stalemates with Old Belvedere, Cork Con and 'Hinch.

All of the scoring came in the first half, a converted try from flanker Ryan Murphy putting Dolphin ahead, before Ballynahinch responded with a penalty try that full-back Chris Quinn converted.

Dolphin, who gave starts to Munster flanker Dave O'Callaghan and league veteran Barry Keeshan at out-half, came under increasing pressure after tight-head James Rochford was sin-binned on the stroke of half-time.

But the sides could not be separated during a tit-for-tat second period. Ballynahinch scrum-half Aaron Cairns was yellow-carded in the 70th minute and there were missed drop-goal attempts at both ends in a frantic finish.

Meanwhile, Clontarf's grip on the league trophy was loosened a little bit more as Cork Constitution beat the defending champions 13-10 at Temple Hill.

Clontarf's fourth loss in their last five Division 1A encounters leaves them 10 points behind leaders Terenure College, whose 29-match winning streak was brought to an end by Lansdowne (15-13) on Friday night. Clontarf would be worse off but for a hard-earned haul of four losing bonus points and a lone try-scoring one.

Full-back Darragh Lyons landed a 20-metre penalty to get Cork Con off the mark, three minutes in, and he added a second five minutes later as Clontarf struggled to find their rhythm.

The north Dubliners managed to respond with a penalty from returning out-half David Joyce, whose well-struck kick cut the gap to 6-3 for the interval.

The weather deteriorated in the second half and after Lyons watched a penalty attempt drift wide, Clontarf struck for the opening try when a good spell from the forwards yielded a 63rd minute score for tighthead Royce Burke-Flynn which Joyce converted.

That looked to a crucial seven-pointer for Andy Wood's men - until the closing stages when the home side managed to get back on top.

The Leesiders went through upwards of 12 phases to wear down the 'Tarf defence and eventually blindside James Murphy reached over for a decisive 79th-minute try. Young out-half Tomas Quinlan added the extras and Constitution held on to end their two-match losing streak.