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."
The WRU has launched a campaign to create a long term legacy for Welsh club rugby by highlighting the advantages of volunteering. Rhian Edwards, a volunteer at Seven Sisters, has enjoyed many benefits of her volunteering at a grassroots rugby club including being part of the Rugby World Cup volunteer workforce after being nominated by the WRU - and the WRU is asking for more people to develop their 'Welsh rugby roots'.
Wales head coach Warren Gatland and captain Sam Warburton say their first prioirty on Sunday in the opening game of the World Cup is to win against Uruguay and not get overly concerned with points difference.
With only days to go until the biggest rugby competition in the world begins, rugby fans visiting Cardiff this autumn will be able to enjoy a special display at National Museum Cardiff as part of the celebrations surrounding the Rugby World Cup.
Geraint John has taken up the new role of WRU elite coach development manager having arrived in Wales last week. WRU TV caught up with him at the WRU rugby department's strategy day at the Millennium Stadium.
The entire Welsh Rugby Union Rugby Department gathered at the Millennium Stadium earlier this week where WRU Head of Rugby Josh Lewsey looked back on a year where structural and strategic changes have seen significant progress made
The Welsh Rugby Union has released a specially produced video to spearhead a new campaign to help promote the values of rugby union. The video, entitled Let us Play underpins the WRU rugby department's philosophy - to engage, transfer and retain players, coaches and referees.