An error-strewn contest didn’t come alive until the final quarter when the extra energy and goal-kicking prowess of outside-half Lloyd Bradley propelled them to glory.
Bryncethin had been overcome 32-24 by Llanharan in the WRU National Bowl Final a year ago but have been undefeated this season and came to the fore to see off Nantyglo.
The Bridgend club, who had Wales and Ospreys centre Owen Watkin on their coaching staff and his elder brother Geraint at scrum-half, had a bit more craft.
Hooker Dafydd Evans got their try but a conversion and ?? penalties from Bradley were to prove crucial with Nantyglo missing three attempts at the sticks.
Nantyglo had started strongly but could have fallen behind had Bradley not dropped the ball as he attempted to intercept a pass. If he had held on to the ball, the outside-half would have had a clear sprint to the try-line.
The Gwent village club – nine buses with their supporters had made the trip to Cardiff with others travelling by train and rail, kept up their assault but second row Llewellyn Edwards was held up over the Bryncethin try-line.
Bryncethin settled and it was a stalemate for most of the half, Nantyglo eventually taking the lead with a penalty from outside-half Richard Powell.
It came following a break from centre Dan Phillips. He found Dylan Tomkins but the wing cut back inside and he was halted. However, Bryncethin had infringed, allowing Powell to find the target from a central position about 30m out for a 3-0 advantage.
Nantyglo blindside flanker Sam Collier charged away and it took a covering tackle from Bryncethin prop Ieuan Davies to stop him. Players on both teams were puffing in the heat and on the fast surface of the Principality Stadium.
Bradley drew Bryncethin level just before half-time by finding the target with a difficult penalty. They were warming to the task and finished the half strongly by being prepared to run from deep.
Powell missed a chance to put Nantyglo back in front by miscuing a penalty attempt. Bradley didn’t have any problem at the other end, making it 6-3 in favour of Bryncethin by squeezing a scrum penalty just inside the far upright.
Powell was off-target for a second time with a penalty and they were on the back-foot as Bryncethin put together the best passage of play of an error-strewn encounter.
The pressure told with Bradley getting another shot at goal to double their lead to six points. They were more comfortable with ball in hand but their big moment came when a clever line-out ploy saw Evans scoring in a corner. Bradley converted and they had a 13-point buffer.
Nantyglo hit back with an unconverted try from replacement prop Ryan Lane to reduce the deficit to eight points but scrum-half Jordan Francis put a foot in touch after a rampaging Damian Jones had done the spade-work.
They continued to throw everything at Bryncethin with hooker Tom Phillips going over for Spencer Cawley to convert but it was not to be…
Bryncethin: Gruffydd Davies; Shane Howells, Dan Howells, Iwan Veasey, Sion Summers; Lloyd Bradley, Geraint Watkin; Connor Buckle, Dafydd Evans, Ieuan Davies, Tobias Hunt, Mark Thomas, Rhys Bridgeman, Connor Law, Morgan Griffiths (capt).
Subs: Rhys Pilliner, Sam Jervis, Will Thomas, Sam Shillibier, Scott Ryall, Steven James, Cai Bradley, Kristian Stenner.
Try: Evans; con: Bradley; pens: Bradley (4).
Nantyglo: Richard Dennington; Dylan Tomkins, Liam Volkes, Dan Phillips, Jordan Baugh; Richard Powell, Tom Bainton; Todd Metcalfe, Tom Phillips, Richard Jones, Llewellyn Edwards, Lloyd Williams, Sam Collier, Ryan Bevan (captain), Steven Jones.
Subs: Ryan Lane, Aled Phillips, Greg Chivers, Owen Thomas, Phil Sargent, Jordan Francis, Damian Jones, Spencer Cawley.
Tries: Lane, T Phillips; con: Cawley; pen: Powell.
