Matt D'Arcy heated up a bitterly cold Belfield Bowl with a terrific hat-trick of tries as Clontarf claimed a 38-17 bonus point win over UCD in Ulster Bank League Division 1A.

D’Arcy, who could play an important role for the Ireland Club international team in the coming weeks, scored three of Clontarf’s six tries against a College side that was missing eight Ireland Under-20 internationals, including the likes of Garry Ringrose, Billy Dardis, Ross Byrne and newly-appointed captain Nick McCarthy.

It was a vital result for the defending champions after their 35-0 hammering by high-flying Lansdowne last time out. It was UCD who hit the front inside five minutes as Rob Keogh's poor clearance kick was run back and centre Stephen Murphy was fed for a sidestepping run to the line.

Liam Bourke, kicking in the absence of Byrne, converted before Clontarf replied in the 11th minute. D'Arcy's initial chip gave them good field possession and a subsequent break from the centre, coupled with a nice offload from prop Royce Burke-Flynn, put winger Rob McGrath over for the visitors' opening seven-pointer.

There were near misses as Bourke sent a penalty wide and D’Arcy knocked on an attempted intercept. The swirling wind nudged the ball off the tee for another Bourke penalty attempt - his drop-kicked effort sailed wide - but the UCD outhalf nailed a 25th minute kick from the left touchline for a 10-7 lead.

Clontarf looked the more fluent side approaching half-time and they edged ahead (12-10) when hooker Rory Litchfield barged through the heart of the UCD defence, the ball was quickly moved wide and the supporting Liam Og Murphy put D’Arcy over for an unconverted try.

Sam Coghlan Murray missed an opportunity to combine with the overlapping Adam Byrne when he was held in a tackle and Jordan Coghlan then knocked on inside the Clontarf 22 as the UCD errors began to mount.

Tellingly, Clontarf enjoyed a purple patch on the restart as the ever-willing D’Arcy dashed 60 metres downfield - taking advantage of a Conall Doherty slip - to touch down to the right of the posts. David Joyce added the extras.

UCD were denied once more by a knock-on as they attempted to capitalise on a Karl Moran sin-binning, while replacement Doherty also went close as the north Dubliners dug deep in defence.

After a Joyce penalty miss, Clontarf secured the bonus point when good hands released D’Arcy to go over unopposed for his eighth try of the campaign which Joyce converted. The latter was duly replaced with those Club international fixtures against Scotland and France coming up over the next few weeks.

UCD gave way again when young Clontarf loosehead Ivan Soroka grabbed their fifth try of the day. A consolation try from Tom Fletcher followed before Andy Wood’s men had the final say, with scrumhalf Sam Cronin sniping over from the back of a ruck.

Leaders Lansdowne also chalked up another bonus point, registering their eighth league victory on the trot as they overcame Ballynahinch 39-18 on the Aviva Stadium's back pitch.

Ballynahinch made the early running thanks to an Aaron Cairns try, and two booming penalties from Chris Quinn had them leading 13-10 with the interval in sight. But Mike Ruddock’s men fought back to lead 22-13 at the break and Ross Adair’s seventh league try was Ballynahinch’s only score of a one-sided second half.

Lansdowne's firepower is proving too much for their play-off rivals at present, with 74 points scored in their last two games. They were helped along the way today by a first half penalty try, but their backs were in match-winning form again with deadly duo Tom Farrell and Cian Kelleher, along with replacement Foster Horan, touching down and Tyrone Moran and fit-again Leinster 'A' lock Tadhg Beirne completed the six-try haul.

Meanwhile, St. Mary's College boosted their survival hopes with a nail-biting 15-13 triumph at Temple Hill, making it two successive wins for Peter Smyth's charges.

The Dubliners remain second-from-bottom but are now six points clear of Dolphin and just two behind eighth-placed Young Munster. Although Mary's fell behind to an early Tomas Quinlan penalty, the wind-backed Cork Con outhalf was off target with a series of other kicks.

That allowed the visitors to take a 10-3 lead into the break, scrumhalf Dave Fanagan collecting a try against the run of play in the 29th minute and full-back Ray Crotty supplied the other five points.

Tom Tierney’s men got on top during the third quarter, though, with Quinlan converting a 46th minute penalty and after three scrums close to the Mary’s line, a hard-earned penalty try was turned into seven points was Quinlan.

However, Constitution were left stunned when elusive right winger Ryan O’Loughlin sidestepped his way through for Mary’s second try of the afternoon and the hosts could not erase the two-point deficit during a tense forwards-dominated finale.

Old Belvedere also picked up a morale-boosting victory at home to Young Munster, racking up four tries as they ran out comprehensive 38-18 winners over the Cookies at Anglesea Road.

The result lifts ‘Belvo up to seventh in the standings and keeps them within four points of the play-off positions - Cork Con currently occupy the last spot. It was certainly a day to remember for Paul Cunningham’s side as they put an end to their five-match losing streak.

Old Belvedere, who bagged an early penalty try, were 13-0 to the good by the time Gearoid Lyons slotted a 22nd minute penalty for Young Munster. A Cathal O'Flynn try widened the margin to 23-8 by half-time and further touchdowns from industrious lock Conor Owende and star fullback Daniel Riordan had the hosts out of sight. Winger Glynn kicked 18 points in all, taking his tally for the current league run to 99.

Terenure College benefited from some clinical finishing as they made it back-to-back successes in the top flight with a 31-18 dismissal of bottom-placed Dolphin at Lakelands Park.

Second-placed Terenure, who are seven points behind Lansdowne and seven ahead of Clontarf, stayed on course for the semi-finals as centre Stephen O’Neill created the openings for first half tries from Ian Hanly and Harry Moore (his eighth of the campaign).

Dolphin trailed 14-6 at the break following two Rory Scannell penalties, but profited from Robert Duke’s yellow card when experienced number eight John Quill drove over for a maul try which Scannell converted.

Just three minutes later, Terenure responded as excellent approach work by Kevin and Mark O’Neill teed up lock Kevin O’Dwyer for his side’s third converted try. But the Corkmen hung in there thanks to a well-taken five-pointer by replacement prop Ken O’Halloran.

Having replaced Mark O’Neill at outhalf, Jake Swaine then took centre stage by running in Terenure’s bonus point score which he converted himself. O’Neill returned to replace his brother Kevin O’Neill at scrumhalf and his late penalty confirmed the 13-point winning margin.