Veteran Anthony, 41, scored the winning try in his final match before retiring to give Birchgrove a shock 7-5 win over promotion-chasing BP Llandarcy in Division Four South West.
Glynneath beat Resolven 23-17 while Abercrave ensured Alltwen's miserable season ended with a 33-26 win. Pontyberem hammered demoted Seven Sisters 45-12 while Cwmavon stunned hosts Tonmawr by claiming a 37-19 victory.
Banwen edged out Brynamman to hold off the threat of relegation in Division Three South West with a hard earned 22-12 victory.
Champions Mumbles also ended the season in style by thrashing Vardre 45-10 with Andy Evans scoring four tries. Heol-y-Cyw finished runners-up, although they crashed to a 50-18 reverse against Skewen while third-placed Tondu hammered the final nail in Bryncoch's coffin as they were relegated with a 46-15 trouncing. Dean Thomas grabbed a brace of tries, but Nathan Townley stole the show with 19 points.
Division Five West basement boys Bynea rounded off a dismal season with another loss, going down 24-10 to Penygroes. Tenby saw off Hendy 27-21 while Morriston proved too strong for Pembroke as they won 15-10 in Division Four West.
In Division Five South Central, Glyncorrwg maintained their march to the title as they won their third match a week against Cefn Cribbwr after Gareth Goodridge inspired them to a 19-9 success.