The Ospreys under 16s booked their place in the final of the WRU Age Grade Championship courtesy of a bonus point victory over Blues North at Llandarcy.
Meanwhile it was heartache for Blues South who missed out on a place against the Scarlets although they won, again, at Tredegar, 19-15 against the Dragons.
A Gerin Eldred try for the Dragons left the South trailing 5-0 at the interval; but a rousing second half performance saw the visitors home, if only just.
James Benjamin bagged a second try for the Dragons with Ethan Davies converting and adding a penalty for good measure. However, when the South discovered the level of control that had taken them into contention going into the game, they crossed for the only time through prolific scorer Osian Davies.
Gareth Thompson, the side's leading scorer this season, converted the try and made sure that the South were at least in with a chance of reaching the last two, with three penalties and a drop goal.
John Richards, team manager at the Blues South, said; "We gave it our best shot and can be pleased with our effort this season.
"To the credit of the Dragons, they might not have had a place in the final to play for, but the threw everything at us. It was a strong game and very enjoyable."
Meanwhile the Ospreys booked their place in the final with coach David Jones' side running out comfortable 35-3 winners over Blues North.
Lewis Montague gave the North an early lead with a penalty before the Ospreys cut loose and scored five tries, including two from the second row Dewi Parry.
His first helped the hosts into a 7-3 interval lead and after crossing for a second 10 minutes into the second half, the Ospreys made sure of maximum spoils with further tries from Matthew Jenkins, Evan Yardley and Sam M Davies.
Outside half Sam Davies kicked five conversions to put the icing on a fine team performance.
The Scarlets, who went into their final game against the Dragons with a 100 per cent record, almost came unstuck as the visitors produced an outstanding display at Parc y Scarlets.
The Dragons dominated the first half and turned around six points to the good courtesy of two penalties.
After the interval, the Dragons maintained the intensity level, but ill discipline started to creep into their game. The Scarlets closed the gap with a try from scrum half Gareth George with Jordan Williams, who had already kicked a penalty, converting.
The Dragons again struck with a brace of penalties and an unconverted try, but the Scarlets made sure of a 17-17 draw thanks to a late try from Daniel Thomas that Williams converted from wide out.
The Under 16 Regional Championship final between the Ospreys and the Scarlets will take place at St Helens, Swansea at 7.15 on Wednesday 10 February. Tickets are £3 for adults, free entry for Under 16s. Spectators are kindly requested to enter St Helens via Bryn Road.
The WRU has launched a campaign to create a long term legacy for Welsh club rugby by highlighting the advantages of volunteering. Rhian Edwards, a volunteer at Seven Sisters, has enjoyed many benefits of her volunteering at a grassroots rugby club including being part of the Rugby World Cup volunteer workforce after being nominated by the WRU - and the WRU is asking for more people to develop their 'Welsh rugby roots'.
Wales head coach Warren Gatland and captain Sam Warburton say their first prioirty on Sunday in the opening game of the World Cup is to win against Uruguay and not get overly concerned with points difference.
With only days to go until the biggest rugby competition in the world begins, rugby fans visiting Cardiff this autumn will be able to enjoy a special display at National Museum Cardiff as part of the celebrations surrounding the Rugby World Cup.
Geraint John has taken up the new role of WRU elite coach development manager having arrived in Wales last week. WRU TV caught up with him at the WRU rugby department's strategy day at the Millennium Stadium.