The Under 18s won 27-20 at Machen with Kaya Harding claiming the Player of the Match award with a fine performance.
For the winners Gwen Harries (2) and Sara Williams scored tries.
The U15 result proved more convincing as the Dragons ran out 43-5 victors, racing over for seven tries in the process.
The Dragons led 19-0 at the break with resilient and coordinated defence ensuring RGC 1404 faced a tough afternoon.
Josie Price (2), Megan Daley, Charmaine Crook, Sophie Johnson, Charlotte Lewis and Annie Bevan scored tries with Daley adding four conversions.
