Dragons A were defeated 17-8 by Cardiff Blues A in a closely-fought friendly at Ystrad Mynach on Wednesday afternoon.
With player development and game time central to the behind closed doors fixture, a young Dragons side battled hard throughout with their regional rivals.
Scrum half Dan Babos grabbed a second half try, but a strong defensive performance from the visitors secured victory.
Cardiff Blues A struck first as scrum half Ellis Bevan darted over in the eighth minute and his score was converted by Luke Scully.
A quick tap and go by opposite number Babos looked to spark Dragons A into life before the forwards earned a penalty that was confidently slotted by Arwel Robson.
There were some thundering tackles going in from both sides before the hosts were held up just short before a penalty saw Blues clear danger.
Dragons A lost prop Josh Reynolds to injury just after the half hour mark and mounting home pressure came to nothing as the visitors held out to the break.
The home side were made to pay for missed opportunities as a try from Harri Millard, converted by Ben Thomas, extended the Cardiff Blues A lead just after the interval.
Dragons A, though, hit straight back as a driving lineout was forced over in the corner with scrum half Dan Babos the man to dot down. Josh Lewis saw his conversion attempt drift just wide.
A penalty from Thomas extended the Blues advantage while a brilliant line break from David Richards almost resulted in a second home score and Rio Dyer looked to race away but was pulled back for a forward pass.
The visitors were reduced to 14 men for the final eight minutes after a yellow card, but held strong to ensure they left Ystrad Mynach with the narrow victory.
Timeline:
08m Bevan t Scully c 0-7
16m Robson p 3-7
42m Millard t Thomas c 3-14
45m Babos t 8-14
53m Thomas p 8-17
Dragons A: Dafydd Howells, Owen Jenkins, Deon Smith, Aneurin Owen, Rio Dyer, Arwel Robson, Dan Babos; Josh Reynolds, Rhys Lawrence, Chris Coleman, Ben Carter, Max Williams, Huw Taylor, George Young, Lennon Greggains
Replacements: Conor Maguire, Luke Yendle, Ed Scragg, Ben Moa, James Benjamin, Luke Baldwin, Will Reed, Josh Lewis, Connor Edwards, Joe Thomas, David Richards