The Ospreys Under-18's went down 40-27 to the Scarlets in a see-saw game at Llandovery RFC on Wednesday evening.
The young Ospreys went in at the break 13-6 ahead, thanks to tries at either end of the half from wing Bowdy Davies and second row Ashton Evans, along with a penalty from Cameron Clement, James Russell replying for the Scarlets with a brace of kicks.
The Scarlets raced into the lead after the break, with tries from Iolo Evans, Luke Treharne, Rheon James and George North, along with a further 14 points from the boot of Russell, and although the Eyasses were able to add another try through Scott Kelly, they were unable to claw their way back into the game.