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."
Wales U20 duo Leon Brown and Lloyd Lewis face a busy couple of weeks ahead. Not only will they have a Junior World Championship to take part in, they are both sitting A Level exams during the competition.
Wales U20 face a tough group in the Junior World Championship with France, England and Japan lying in wait but Attack coach Jason Strange and back rower Tom Phillips are looking forward to the campaign ahead.
Angus O'Brien has quickly settled into the Wales Sevens squad after solid performances in Hong Kong and Japan. With two rounds remaining in Glasgow and Twickenham on the World Series, WRU TV's Graeme Gillespie chats to the rising star.
Wales winger Luke Morgan has established himself as one of the deadliest finishers on the Sevens World Series. WRU TV's Graeme Gillespie catches up with him on the eve of this weekend's round in Glasgow.
All roads lead to Cardiff on Sunday for the SSE SWALEC Finals Day at the Millennium Stadium. Cambrian Welfare tackle Ystradgynlais in the Bowl final, Ystrad Rhondda play Newcastle Emlyn in the Plate final while defending champions Pontypridd face Bridgend in the Cup final.
WRU Chief Executive Roger Lewis, Deputy Minister for Culture, Sport and Tourism Ken Skates and WRU Chairman Gareth Davies earlier this week launched a new competition in conjunction with the WRU unveiling its archive room.
Welsh players and management joined Deputy Minister for Sport Ken Skates at the Pierhead Building, Cardiff Bay earlier this week to reveal the Union's pioneering school-club hub initiative has been so successful the project will now almost double the scale of the original project.
The Scarlets, Newport Gwent Dragons, Cardiff Blues and the Ospreys look ahead to Judgement Day III which sees the Blues take on the Ospreys (2.30) and the Dragons tackle the Scarlets (4.45pm) at the Millennium Stadium tomorrow afternoon.
Ystradgynlais and Ynysddu played out a titanic struggle at Taffs Well in the SSE SWALEC Bowl semi-final. At the end of the game neither team could be separated after a 15-15 stalemate but Ystradgynlais go through on try count.