Tumble overcame a tricky test against Aberystwyth with a 38-7 win to maintain the lead in Division Three West. Llangenfi remain hot on their heels though, after their 49-24 victory against Ammanford while bottom-placed Pontarddulais were edged out 27-21 against Lampeter.
Mumbles took a major step towards an immediate return to Division Two after they brushed aside Cwmgorse 45-7, while all the other contenders surprisingly slipped up.
Brynamman were victors in the basement showdown with Banwen 49-25 to boost their survival hopes. Llanydder, who have already wrapped up the title in Division Four, eased past Tenby United 23-16 while Pembroke were beaten by Crymych 10-0.
Division Four South West pacesetters Briton Ferry gained a valuable win at Taibach and BP Llandarcy boosted their title hopes and ended Glynneath's in the process following their 35-17 success.
Tycroes lead the way in Five West, although Aberaeron crushed St David's 44-0 while Llamgwm's season improved with a 22-7 away day joy at Fishguard.
In Division Five South West, Neath Athletic are now favourites to clinch the title following their 75-12 hammering of Cwmtwrch.
Glyncorrw lead the way in Five Central after they swept Pyle aside 36-10 but Maesteg Celtic cannot be discounted as they demolished Blaengarw 45-5.