It was quite a weekend of action throughout the divisions but the Division 2B Ulster derby between Rainey Old Boys and Belfast Harlequins was one of the most significant.
Rainey ended up winning 31-21 at Hatrick Park and, with two games to play, need one more win to secure second place and a home play-off semi-final.
Quins can no longer finish any better than ninth spot and look certain to be in a relegation play-off though City of Derry can mathematically still end up above them. Rainey scored tries from Tim Barker, Jody McMurray and Ronan McCusker and were awarded a penalty try while Christian Bennison and Conor McAuley crossed for Quins who led 11-10 at the break.
Derry were beaten 48-10 at Skerries while sixth-placed Dungannon - playing their second game in a week - lost 31-7 at Old Crescent, which saw the unbeaten Limerick side secure the league and promotion to 2A.
There was entertainment aplenty at the Dub where Queen's University and Highfield played out a 13-try thriller in their 2A meeting.
The sixth-placed students, though, were on the wrong end of the 43-36 scoreline but came away with two bonus points while Jake Milliken bagged a brace from their total of six touchdowns.
Leaders Malone beat Cashel 22-17 at Gibson Park, where Jack Owens scored one of their two tries, and look set to win the league and be promoted with one more victory.
In fifth, City of Armagh surprisingly lost 30-29 at bottom team Corinthians which is a blow to their play-off hopes.
Omagh's 44-22 result at Bective saw them move up to third in 2C with Scott Elliott and Adam Longwell both getting braces, while Bangor's 37-8 defeat at home to Midleton leaves them in fifth but only six points ahead of the relegation zone.
Meanwhile, Instonians will be Ulster's representatives in the forthcoming AIL Qualifying Round-Robin so now have an opportunity to return to the competition after a gap of four seasons.
Their 45-7 victory over Cooke secured the Kukri URC Division One title to move them into position for the AIL qualifiers.
2A: Corinthians 30 Armagh 29, Malone 22 Cashel 17, QUB 36 Highfield 43
2B: Old Crescent 31 Gannon 7, Rainey 31 Quins 21, Skerries 48 Derry 10
2C: Bangor 8 Midleton 37, Bective 22 Omagh 44