After the Blues North recorded a 17-0 victory over the Dragons U16, the Blues South were unable to make it a double for the region as they went down 26-24 to the Scarlets.
Elliott Jones crossed for a brace of tries for the Blues and Diggy Bird weighed in with a try, penalty and three conversions.
However, tries from Kirby Myhill, Jamie Kaijacks, Lawrence Reynolds and Dafyn Dafydd earned the Scarlets a crucial victory which keeps alive their chances of reaching the final.
