There are just four points separating the top three clubs, with Old Wesley in the middle.
Wesley's cause will be helped somewhat in that they finish off the regulation phase of the league with games against Barnhall and Sunday's Well, who are 13th and 14th in the table respectively.
Corinthians' final day trip to Naas will be crucial, especially if they fail to beat Queen's at home, while the Belfast students have a vital home date with fourth-placed Midleton in the last round of matches.
Former leaders County Carlow, now down in fifth, are really up against it after losing 27-20 away to Queen's. Meanwhile, Nenagh Ormond still have an outside chance of reaching the semi-finals, after beating Midleton 14-8 at home.
In the relegation zone, Waterpark's drop to the junior ranks was confirmed when they suffered their 13th defeat of the league campaign - a 49-3 loss to high-flying Corinthians.
The Galway men, facing into the wind, were 18-3 ahead at half-time at Ballinakill. Winger Ricardo Santos kicked an early penalty for Waterpark but tries from Shane Geraghty, Kieran Dolan and James Buckley helped the visitors seize control.
Wayne Williams and Darin Claasen both touched down, after the restart, to strengthen Corinthians' lead and with Waterpark's defence not standing up to the increased pressure, further tries from Buckley, Claasen and the very effective Michael Roche completed the rout.
Banbridge boosted their chances of survival by claiming a 10-8 Ulster derby win over Ards at Hamilton Park last Saturday.
Second-from-bottom Bann scored a late try through Simon McKinstry to register their fourth win of the campaign, which lifts them up to 21 points, level with Barnhall and Sunday's Well above them.
As in previous seasons, whoever finished second-from-bottom in the Division Three table will face a promotion/relegation play-off against the runners-up in the AIB League round robin qualifying series.
A swirling wind played havoc with Ards and Banbridge's play and Bann's Neville Farr missed a 19th-minute penalty chance before flanker Darren Cochrane broke through for the game's opening try on the half-hour mark.
5-0 down at the break, Ards missed a penalty opportunity before getting over for an unconverted try. The Bann defenders dithered on a loose ball and Ards winger David Armstrong swept the ball up before racing over unopposed for an opportunist try.
Drama followed when, with just 10 minutes remaining, Ards' Michael Lawton landed a penalty goal from 35 metres out, after a high tackle had been spotted.
However, Banbridge grabbed the game's deciding score off the restart when number 8 Matthew Irvine blocked a clearance kick and McKinstry was on hand to gather the ball and dash over the line for a crucial try.
Naas and Nenagh both recorded home wins, with the Kildare side accounting for Suttonians on a 23-13 scoreline and the men from Tipperary edging past Midleton (14-8).
Midleton, who included Munster backs coach Jason Holland at out-half and former provincial star John O'Neill on the wing, trailed by 9-5 at the break at New Ormond Park.
Three John Lillis penalties had the home side ahead on the scoreboard and they scored an outstanding second half try to crown the win.
Ger Heremse launched a counter attack, after gathering a long kick, and set up a ruck on halfway. Centre Vima Tuidraki chipped over the top and regained possession to make further yardage before Mike Fogarty snipped over from a close range ruck.
Meanwhile, Naas pulled clear of the relegation battle with a hard-fought win over Suttonians. They led 13-3 at half-time and got off the mark in the seventh minute thanks to a David Aherne penalty.
Full-back Aherne, who had an excellent game, then converted Andy Kearney's 29th-minute touchdown which came after good work from Regan Phipps.
Aherne and Suttonians' Thomas Campbell swapped penalties as the first half came to a close, but a loss of discipline in the third quarter saw the Dubliners lose prop Gareth Connolly and scrum half Joe Walsh to the sin-bin.
Naas tightened their grip on the game when an Aherne-converted try put them 23-3 ahead.
But, to their credit, Suttonians produced a rousing final 15 minutes, during which full-back David Walsh and replacement Noel Hehir both got over for consolation tries.
Elsewhere, tries from Dave Twohig and Barry Hanrahan inspired Sunday's Well to a 12-3 triumph over Barnhall at Musgrave Park, and Rainey Old Boys gained a 14-7 success over their Ulster rivals Portadown at Hatrick Park.
A try from Peter Boyle, two penalties from player-coach Rhys Botha and a drop goal from Jerome McMurray did the business for Rainey.
Old Wesley maintained their promotion push with a 40-6 hammering of Connemara at Donnybrook.
The Dublin 4 outfit's second successive bonus point win was set up by tries from Alan Large (2), Barry McLaughlin, Colin Wallace, Alan Thompson and Dave O'Leary.
At Dub Lane last Saturday, Queen's edged out Carlow in a terrific battle. The midlanders, coached by Jason Jones, came back from being 17-0 down after 36 minutes to make a real game of it.
Carlow conceded a rake of penalties but after battling back superbly to 22-20, they allowed Queen's blindside flanker Paddy McGowan too much freedom on the left wing as he slipped through for the match-winning try in injury-time.
DIVISION THREE RESULTS: Saturday, March 28
Ards 8 Banbridge 10, Hamilton Park
Naas 23 Suttonians 13, Forenaughts
Nenagh Ormond 14 Midleton 8, New Ormond Park
Old Wesley 40 Connemara 6, Donnybrook
Queen's University 27 County Carlow 20, Dub Lane
Rainey Old Boys 14 Portadown 7, Hatrick Park
Sunday's Well 12 Barnhall 3, Musgrave Park
Waterpark 3 Corinthians 49, Ballinakill
DIVISION THREE FIXTURES TO COME:
Saturday, April 4 -
Connemara v Rainey Old Boys, Monastery Field, 2pm
Saturday, April 11 -
Banbridge v Nenagh Ormond, Rifle Park
Barnhall v Old Wesley, Parsonstown
County Carlow v Naas, Oak Park
Corinthians v Queen's University, Corinthian Park
Midleton v Waterpark, Towns Park
Portadown v Ards, Chambers Park
Suttonians v Sunday's Well, John J McDowell Memorial Grounds
Saturday, April 18 -
Ards v Connemara, Hamilton Park
County Carlow v Suttonians, Oak Park
Naas v Corinthians, Forenaughts
Nenagh Ormond v Portadown, New Ormond Park
Old Wesley v Sunday's Well, Donnybrook
Queen's University v Midleton, Dub Lane
Rainey Old Boys v Barnhall, Hatrick Park
Waterpark v Banbridge, Ballinakill
Saturday, April 25 - Semi-finals and promotion/relegation play-off
Saturday, May 9 - Final