Shannon for their part have now completed their programme and must wait on the last series of matches before they'll know if they'll be involved in the knock-out stages.
On Saturday they led at the break after Mossie Lawlor had scored a try - created by Brian Touhy - in the corner in the 28th minute but that lead lasted all of ten minutes into the restart and when Cronin Healy scored first and that was followed by a second try for winger Tomas O'Leary.
Pat McCarthy converted both those scores and when Under 21 international Brendan O'Connor crashed over for the fourth try the bonus point was secured.
Lawlor scored his second try on the stroke of full time to reduce the deficit to eight points but the consolation of a crucial bonus point drifted away when Tommy Cregan's difficult injury time penalty went narrowly wide.
Belfast Harlequins and Buccaneers are in third and fourth place respectively, both now just five points off Shannon. Harlequins were 32-17 winners in Castle Avenue where they gained the bonus with four tries while the Buccs also scored 32 points and four tries at home to struggling Lansdowne.
Harlequins are home to a Ballymena side who are the only club left who could still edge into the knock-out stages. They beat Dungannon 15 love on Saturday and would need to beat their northern neighbours on April 17th while Buccaneers travel to Stevenson Park on the final day to play a Dungannon side who will be desperate for points to ensure they remain in the top tier.
Perhaps the most extraordinary come-back of the season occurred in Oak Park when Galwegians scored three tries in the last 12 minutes to beat the home side 28-32. With the bonus point in the bag Co Carlow looked to be cruising to victory and at the same time sealing Galwegians' fate before tries from James Littleton, Cathal Murphy and Brendan Bartley gave the westerners only their third league win of the season.
Who gets promoted from Division Two will be decided on the final day when League leaders Old Belvedere take on third placed UL Bohemians at Anglesea Road. A win for the home side, who beat Barnhall 16-5 on Saturday, will see them promoted but Trinity in second place could benefit if Belvo slip up. The students beat Thomond 22- 3 in Limerick and wind up their campaign in Limerick with a tie against Old Crescent who still entertain hopes of making the play-offs and the opportunity to retain their title.