O'Brien was yellow carded in the second half, but the Dragons were unable to make hay whilst the scrum half was off the field. Marcus Johnston, with two tries, plus a penalty and conversion from Rhys Jones kept the Dragons in the hunt, but the Ospreys were strong enough to hold off the home challenge and set up a final showdown with the Scarlets.
Having secured their passage through to the final last moth, the Scarlets finished off their pool campaign with a 22-8 victory over Cardiff Blues. The Scarlets scored tries through wing Alec Jenkins (2) and Steve Martin with Sion Crabtree weighing in with two conversions and Darren Allinson adding a penalty.
The Scarlets will play Blues North TONIGHT (Wednesday 23 Feb) at Stradey Park in the rearranged Round 6 U16 fixture (kick-off 7.15pm).