Loughor were knocked off the top of SWALEC League Division Two West after they lost at home to Kidwelly
Craig Thomas scored the only try of the first-half for Kidwelly, but Loughor were leading 9-7 until 11 minutes before the end of the game. At this point, the visitors won a contentious penalty, which was kicked by Leighton Walters.
Kidwelly then crashed over twice more, through Jason Smith and Rhys Jones, to pick up a 22-9 win. The new Division Two West leaders are Builth Wells, who were also late winners.
They trailed visitors Llandarcy 9-3 going into the last minute before centre John Thurston crossed for a try.
Thurston then put over the resulting conversion, which was the last kick of the game, to see the Bulls nick the game by a point and head the table.
Bridgend Athletic stay in third after a five try victory over Penclawdd. Mark Bennett grabbed a brace of tries, with others coming from Simon Mustoe, Rob Coles and Rod Davies, as Athletic won 38-3.
In the clash of the top two in Division Three West, second-placed Pontyberem reduced the gap on Aberystwyth to just two points after they won 13-5 at the league leaders.
Two unconverted tries from Dan Hawkins and Justin Lloyd, plus a penalty from Mike Sauro saw Bont secure victory at Plascrug.
Division Four West leaders Llandeilo trounced Cwmgors 37-5, and at the top of Division Five West Milford Haven overtook Cefneithin, who did not play, by narrowly beating Aberaeron 19-15.
The last five years have been an emotional rollercoaster on and off the pitch for RGC1404. Promotion to the Principality Premiership was the culmination of five years of hard work and investment in North Wales. WRU TV caught up with prop Joe Simpson, who was one of the first intake of WRU North Wales Academy players in 2010.
Ebbw Vale captain Damien Hudd picked up the biggest accolade of the night at the 11th Principality Premiership Awards Evening held at Principality Stadium, after leading his side to the title for the first time.
Wales assistant coach Robin McBryde is predicting a tough battle against England on Sunday despite the fact they may not be considered to be at full strength. Players will be out to impress Eddie Jones which makes England a dangerous proposition, he says.
Wales U20 captain Tom Phillips and performance psychologist Dr Rich Neil explain why spending three days at Monmouth RFC has further strengthened the togetherness of the squad ahead of the #WorldRugbyU20s