A very competitive game at Abercynon saw Blues North U16 mark their first game of the regional age grade competition with a narrow 17-15 win over the Scarlets.
It was the Scarlets who took the upper hand during the first period as they caused the Blues defence trouble. And it was not long before the visitors registered the opening score when hooker Matthew Moore crossed the line after sustained pressure from a driving lineout.
The Blues fought back and came close to a number of scores but were frustrated with the final pass going to ground on two occasions. And it got worse before half-time when indiscretion at a ruck resulted in a yellow card for Blues flanker Leon Rogers.
The Blues started the second-half on the back foot and soon found themselves further behind when centre Keiran Jones kicked a penalty to pull the Scarlets further clear.
But a series of second-half introductions saw the Blues' replacements make a massive impact as the home side began to impose themselves on the game. With Blues outside half Calum Hall beginning to get his team playing, the Blues scored a superb try through winger Jarred Evans. Hall added the conversion and the Blues were back in the game.
And the Blues made the most of their momentum and scored a second try courtesy of flying wing Kurtis Williams to secure the win.
A late consolation try from Scarlets' replacement Harry Randall was converted by fellow substitute Joe Chiffi but it was not enough to deny the Blues their first win of the competition.
In the other U16 game to be played, the Ospreys responded to their defeat to the Scarlets last time out with a 7-13 win away at the Dragons.
Despite trailing 7-3 at half-time, two second-half tries from Ben Davies and Regan Grace saw the Ospreys prevail in what was a low-scoring game at Tredegar.
Scrum-half Sior Pearce gave the Dragons the lead with a tenth minute try with Arwel Robson adding the conversion. But this was to be as good as it got for the home side as they failed to score a point thereafter. Matthew Aubrey kicked a penalty for the Ospreys to get them on the board before half-time and tries from Davies and Grace consigned the Dragons to their second consecutive defeat.
Under 18 - Blues 25 Scarlets 21
Wednesday was also a successful evening for the Blues at U18 level as they made it two wins out of two with a 21-25 victory over the Scarlets.
Despite trailing 14-12 at the interval, Dale McIntosh's men fought back in a tight second period to claim the victory at Parc Y Scarlets. Flanker Will Boyde went over for the Scarlets in the 14th minute and fly-Dan Jones added the conversion for a 7-0 lead.
Winger Ellis Wyn Benham responded for the Blues and Jarrod Evans tied the scores by kicking the conversion though the visitors weren't level for long. Just a minute later winger Josh Adams went over to extend the home side's lead with Jones again successful with the conversion.
With 12 minutes of the first-half remaining, Blues' scrum-half Tom Williams got his team back in it with a try and his team never looked back. Evans added a penalty 14 minutes into the second-half and from there the Blues never relinquished the lead. No. 8 Ollie Hitchens went over to extend the cushion with replacement Sam Withers kicking the extra two points.
And although a converted try from Josh Middleton saw the Scarlets narrow the gap, a penalty from Withers saw his side home as the Blues maintained their 100 per cent record.