Defending champions Clontarf became the third team to qualify for the Ulster Bank League Division 1A play-offs when they beat Cork Constitution 43-28.
Third-placed 'Tarf will join Lansdowne and Terenure College in the semi-finals, with Ballynahinch leading the race for fourth spot ahead of the final round of games on April 11.
The north Dubliners outscored play-off rivals Cork Con by six tries to four at Castle Avenue, coming to the fore in the second half with Matt D'Arcy and Max McFarland both scoring braces. Recent Ulster debutant Ross Adair touched down twice as Ballynahinch overcame Dolphin on a 35-28 scoreline at Irish Independent Park. The defeat means the Cork club are now relegated.
The five-point return, coupled with Cork Con's loss, has 'Hinch two points clear in fourth place. Derek Suffern's charges will need to defeat Clontarf at home in two weeks' time to advance to the play-offs.
Scott Deasy came off the bench to convert Ian Fitzpatrick's decisive final quarter try as Lansdowne won their top-of-the-table meeting with Terenure, prevailing 29-20 at Lakelands Park.
Old Belvedere pulled off a tremendous 23-20 comeback win over UCD at Belfield thanks to Daniel Riordan's 65th-minute try and two late 'clutch' penalties from Josh Glynn.
Belvo' are still pushing for that final play-off place as are Young Munster who are now fifth after defeating relegation-threatened St Mary's 18-13. Second-half tries from backs Diarmuid McCarthy and Kolio Hifo got the job done for the Cookies at Tom Clifford Park.
Meanwhile, Garryowen have nipped ahead of Galwegians at the top of Division 1B as the battle for the automatic promotion spot goes down to the final round when the two sides meet at Crowley Park.
Garryowen swept relegated Malone aside in a 34-12 home victory. Their five tries were shared out by the forwards, including the opener from Connacht prop JP Cooney.
Galwegians' five-match winning streak was ended by Belfast Harlequins as the hosts triumphed 36-34 at Deramore Park. Tries from Mark McGrath, Tom Fraser, Frankie Taggart, Sean Reidy and Mark Glover moved wind-backed 'Quins 33-5 clear by half-time. Credit to 'Wegians, wily backs Brian Murphy (3) and John 'Luigi' Cleary (2) led a scoring blitz for the visitors who fell short of a stunning comeback.
Richie Mullane and Niall Horan both scored as Shannon ground out an 18-11 win over Ballymena at Coonagh. Ian Sherwin's young side are now safe in seventh place.
Mossy Lawler finished off UL Bohemians' fifth try as they ensured their Division 1B status for another season with a 32-0 success against Buccaneers. Corinthians will join Malone in dropping down a division after they were beaten 32-11 by Dublin University at Corinthian Park.
Ross Adair (Ballynahinch)
The recent Ulster debutant scored two tries in Ballynahinch's 35-28 win over Dolphin to boost his side's hopes of sealing a play-off spot. A win against Clontarf at home in two weeks would do just that.
One to watch
Diarmuid McCarthy (Y Munster)
The former schools sensation scored his first try for Young Munster as they kept themselves in the play-off hunt.
Number of the weekend
Defending champions Clontarf became the third team to reach the play-offs. There is one remaining spot to be won going into the final weekend of action.