The Ospreys and Scarlets Under 16s bagged victories in the WRU Age Grade Championship last night to put the pressure on previous leaders Blues North.
With the North not playing until Sunday, against North Wales, both regions made hay despite failing to pick up a bonus point.
Two victories in their opening three games became three in four for the Scarlets as tries from Gethin Hunter, Richard Bloomfield and Gareth Rees helped them to a 23-12 success over the Dragons at Narberth.
Meanwhile at Llandarcy, the Ospreys defeated Blues South 14-8 to secure a second win of the season.
Rhodri Lloyd gave the Dragons a 5-0 lead inside two minutes with his first try of the season and though Jordan Williams cut the lead with a penalty, Thomas Ashmead, with a try, and Josh Prosser's conversions helped the visitors into a 12-3 lead.
It was a different story after the interval with Hunter crossing for his fourth try of the campaign, after 53 minutes, and Williams adding a conversion and penalty for good measure.
However, it was not until the final quarter that the Scarlets pulled away with Bloomfield and Rees on the mark with tries.
Meanwhile at Llandarcy, a try from Cory Allen and penalty from James Morris kept the South in touch, but the Ospreys made the most of three yellow cards for the South and made sure of the victory spoils courtesy of three penalties from outside half Tom Carpenter and a try from centre Andrew Claypole.
High performance manager Gruff Rees said; "There were elements of the performance that need work, notably our finishing, but there was plenty of honest endeavour and we will take the win."
Whenever Bedlinog tackle Penallta a massive fixure is guaranteed but this Sunday there will be even more emphasis placed on the two rivals when they contest the SSE Swalec Plate final at Principality Stadium.
Ahead of their SSE SWALEC Bowl Final clash with Taffs Well at Principality Stadium on Sunday, Burry Port share their #FABXV nomination with WRUTV in the search for Welsh rugby's greatest volunteers. Everyone can get involved by sending nominations via twitter to @WRU_Community using the hashtag #FABXV
Cardiff Blues prop Gethin Jenkins and Ospreys centre Ben John look ahead to the first game at Principality Stadium in Saturday's double header which is promising to be a special occasion for all Welsh fans.
Carmarthen Quins Director of Rugby Ian Jones and committee member Jeff Thomas along with Llandovery chairman Handel Davies look ahead to Sunday's SSE SWALEC Cup showdown where both teams are out to prove 'West is best'
SWALEC ambassador Shane WIlliams is looking forward to Sunday's Finals Day where the Cup, Bowl and Plate offers a great opportunity for players and teams to experience the magic of playing at Principality Stadium
Carmarthen Quins coach Richard Kelly believes it is an exciting time to be part of the Scarlets region as his side take on local rivals Llandovery in the SSE Swalec Cup final on Sunday, as WRU TV's Graeme Gillespie discovers
Scarlets long serving prop Phil John talks to WRU TV's Graeme Gillespie about Judgement Day IV and SSE Swalec Cup finals day. The last time Llandovery were in the cup final in 2007, the Drovers claimed the spoils with Phil playing a major role in the engine room.
Meet Aberdare coach Luke Thomas whose #FABXV nomination goes to super volunteer Daz with a whopping 10 things he does for the club each week, all except the ironing! You can also join in the search for Welsh rugby's greatest volunteers, by sending your nomination via twitter to @WRU_Community using the hashtag #FABXV
SSE Swalec Cup kings Pontypridd travelled to Swansea, fully expecting a return to their second home but Llandovery had other ideas as they also sought victory in the semi-final to earn the right to play the final at Principality Stadium