With four rounds to go in Ulster Bank League Division 1A, leaders Lansdowne remain in pole position for a home semi-final despite losing a thrilling game to UCD at Belfield on Saturday.
Mike Ruddock's men went down 38-31 to UCD in hugely entertaining encounter that produced ten tries in all - six for the students, including a brace for current Ireland Under-20 international Joey Carbery.
A product of Athy RFC, Carbery was a Leinster Schools Senior Cup winner with Blackrock College last year and won his first Ireland Under-20 caps off the bench recently against Italy and France.
Most of his U-20 international colleagues were rested this weekend, but Carbery, who plays at full-back or out-half, needed game-time and took on the 'impact sub' role with aplomb once again, scoring two decisive second half tries.
It was a vital result for UCD as they are now just two points outside of the play-off spots, and the comeback win completed a notable season's double as they had already beaten Lansdowne away (19-10) in November.
Ruddock's side will be kicking themselves as they led 10-0, 24-15 and 31-22 at Belfield, with a penalty try won by their powerful scrum earning them the bonus point. But they failed to score after that as free-running UCD notched 16 points without reply, adding to earlier tries from backs Bobby Holland, Adam Byrne, Sam Coghlan Murray and Barry Daly.
However, with second-placed Terenure College losing at Clontarf, Lansdowne's lead at the top of the table was actually extended thanks to their two bonus points and they look nailed on to have home advantage in the play-offs.
Another replacement proved his worth at Castle Avenue as USA international Liam Og Murphy's disputed try proved the difference for reigning champions Clontarf in a 16-11 win over Terenure.
Terenure felt there had been a knock-on before flanker Murphy crossed the whitewash in the 54th minute, but referee Kieran Barry awarded it and David Joyce converted to add to his three first half penalties.
'Nure's hopes of hitting back were not helped by the subsequent sin-binning of replacement Kevin O'Dwyer, adding to earlier yellow cards for 'Nure out-half Mark O'Neill and Clontarf's Leinster winger Mick McGrath.
There was very little between the teams throughout, although Terenure would have been the happier at half-time, trailing 9-8 despite playing into a stiff breeze. An O'Neill penalty was followed by flanker Robert Duke's 20th-minute penalty, with Joyce replying off the kicking tee for the hosts.
During O'Neill's sin-bin period, replacement James Thornton booted James Blaney's charges back in front early in the second half. However, thanks to Murphy's close range effort, the north Dubliners took the spoils to close within four points of 'Nure in the table.
Fourth-placed Cork Constitution did enough to warrant a slim 6-3 victory over Young Munster, as these two great rivals failed to produce a try between them at Tom Clifford Park.
The visitors took the four league points on offer thanks to a penalty by young replacement Tomas Quinlan, ten minutes from the end. Tom Tierney's men also picked up the Danaher-Sheehan Cup which is played for annually between the clubs.
Young Munster, who have fallen to second-from-bottom in the standings, will wonder how they lost this one as they were on top for long spells. But they met a very tight Cork Con defence and the visitors were fortunate that the usually deadly accurate Gearoid Lyons missed two penalties approaching half-time.
Cork Con had their Ireland Club international prop Ger Sweeney sin-binned in the 18th minute but the Cookies could not capitalise. Sweeney was replaced by Aidan Slattery and he too was yellow carded after 56 minutes.
Darragh Lyons put the Leesiders in front three minutes into the second half before Gearoid Lyons, the Young Munster centre, finally found his range on the hour mark. Quinlan's winning kick followed from the 22 and try as they might, Munsters were unable to respond.
It was a good day for two clubs in the lower reaches of the table as bottom side Dolphin and St. Mary's College, who have climbed above Munsters into eighth place, both enjoyed home wins.
Once again Munster's Rory Scannell dictated matters for Dolphin, his chip through releasing outside centre Cian McGovern for the only try in their 13-3 defeat of Old Belvedere at Irish Independent Park.
Since the turn of the year the Corkmen have now won three out of four in the Ulster Bank League and the presence of Ireland head coach Joe Schmidt, a special guest at their pre-match lunch, would have also been a source of inspiration.
Leinster's Steve Crosbie landed a 40-metre penalty for 'Belvo, three minutes into the second half, but Scannell's second successful penalty in the 76th minute put the seal on a deserved success for Steve Ford's side.
St Mary's and Ballynahinch shared out eight tries in their exciting tussle at Templeville Road, with full-back Ray Crotty's 12-point kicking haul helping the hosts win out on a 32-25 scoreline.
Prop Brian McGovern's try in the 75th minute was the one that mattered most for Mary's as they clinched their third league victory on the trot. With other results working in their favour, they have moved out of the relegation spots for the time being.
Meanwhile, Galwegians and Garryowen both gained significant ground in the race for promotion from Ulster Bank League Division 1B, as they won today's top four clashes at Eaton Park and College Park respectively.
Despite losing front rowers Doron McHugh and Ciaran Gavin to early arm injuries, Galwegians showed impressive resilience to beat fellow promotion hopefuls Ballymena 25-17 in a real cliffhanger.
The hard-earned result has Matt Brown's men two points clear of Garryowen at the top of the table and they are now seven points better off than third-placed Trinity.
Dublin University's 10-match unbeaten run was ended by Garryowen in another dramatic finish in the capital, as Jamie Gavin's late penalty - followed up by a blocked Trinity drop goal - saw the Light Blues triumph 24-23.
Gavin's kick was Garryowen's only score of the second half. They laid the foundations for victory in the opening 40 minutes during which their starting back-three - James McInerney, Alex Wootton and James Frawley - all touched down for a 21-3 lead.
One of the results of the day in the second tier saw Belfast Harlequins beat a disappointing Shannon side 31-13 at Deramore Park to climb to sixth spot in the standings.
26-21 winners at Thomond Park in November, 'Quins completed the double over the Limerick men thanks to tries from Mark Glover, Ulster's Neil McComb and Junior Bulumakau as well as 16 points from Michael Heaney's accurate boot.
UL Bohemians moved off bottom spot courtesy of a 16-6 defeat of Malone at Annacotty, with Mossy Lawler, the recently-appointed Connacht Elite Player Development Officer, scoring the game's only try.
Division 1A Results
Clontarf 16 Terenure College 11
Dolphin 13 Old Belvedere 3
St Mary's College 32 Ballynahinch 25
UCD 38 Lansdowne 31
Young Munster 3 Cork Constitution 6
Ballymena 17 Galwegians 25
Belfast Harlequins 31 Shannon 13
Dublin University 23 Garryowen 24
UL Bohemians 16 Malone 6
Corinthians 14 Buccaneers 17