The Scarlets welcomed the Blues U15's to Carmarthen Park with both sides realising the significance of the game.
Both sides had won their first games easily so this game was likely to be key at the end of the regional season.
The Scarlets started the strongest but some poor passing allowed the Blues into the game and they ended the first half the strongest with only committed try line defence led by Jodie Williams, Ffion Jones and Emily Coleman keeping out a strong Blues attack.
The second half started like the first with the Scarlets in control but after the break the Scarlets seemed to have a new resolve, and when the ball was moved quickly wide to Sioned Jones, she beat two defenders on the outside to score near the corner flag.
With the conversion attempt wide of the mark, the result was still in the balance and despite the Scarlets dominating possession the Blues backline looked dangerous every time they had the ball, but determined defence from the Scarlets stopped every attack from the Blues.
The last 10 minutes of the game was a battle of wills, but the Scarlets were determined after last season's 0-0 score line not to let their lead slip.
With Chloe Davies and Elisha Butchers winning the breakdown battle and no gaps in the Scarlets backline defence, the Blues had nothing left to offer, and the Scarlets held on for a deserved victory.
With only one try conceded in 10 regional games, the Scarlets defence proved to be rock solid.
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.
Blues strike first in JD III battle - Newport Gwent Dragons lock Andrew Coombs, WRU referee Dylan Llyr Jones and Cardiff Blues hooker Matthew Rees decide dressing room allocations for Judgement Day III
Wales Under 18 captain Calum Haggett has received a conditional offer to read Biomedical Science at St Anne's College, Oxford. WRU chairman Gareth Davies went to meet Calum and Coleg y Cymoedd Principal Judith Evans to wish him luck in his exams and pass on some of his personal experience.
Dodgy tattoos, carthorses, Avatar and soft chins are revealed by Wales Sevens players Tom Williams and Sam Cross as they profile the Wales Sevens squad taking part in Hong Kong this weekend in the latest round of the HSBC Sevens World Series.