Dragons RFC U18s begun their Regional Age Grade Championship defence with defeat against the Ospreys at a cold Centre of Excellence in Ystrad Mynach on Wednesday evening.
Missing a host of players due to senior rugby and injury, the hosts started strongly and opened the scoring through wing Harry Rees-Weldon.
Dragons led by captain Morgan Williams dominated the first half in possession and territory but missed a number of opportunities to extend their lead before half time.
Ospreys defence kept the visitors in the game before an interception just before the break from Luke Davies, and despite the centre being caught by Jack Woods, he managed the offload for wing Llewellyn Hawkes to score.
Fly half Charlie Thomas added the conversion to give his side a 7-5 lead heading into the break.
The second half, in a complete opposite to the first saw with the visitors build on their late first half score to extend their advantage through lock Kyle Harris.
Discipline and line-out trouble gave the Ospreys territory and possession, of which they took full advantage with Kyle Harris powering his way over for his second of the evening.
Before a fourth try and bonus point was sealed by replacement hooker Fin Thomas late on to give his side a 26-5 victory in the season opener.
Dragons now travel North to face RGC this Sunday as they hope to kickstart their RAG campaign with a first victory.