Gareth Bowen helped himself to 22 points as Llanelli Scarlets became the first side to do the double over the reigning Celtic League champions Munster at Stradey Park.
Bowen converted all four home tries, including his own last gasp effort that clinched a bonus point, as a 6,169 crowd was treated to a top quality match containing seven tries.
With first use of the strong wind the Scarlets raced into a 20-3 interval lead thanks to some inspired centre play from Matthew Watkins. He scored the first try and then paved the way for the second by wing Richard Rees.
But far from being down and out, Munster hit back after the break and a kick and chase try from Eoin Reddan raised their spirt. Gareth Williams replied with a debut try for the Scarlets, but two tries in five minutes by Irish wing Anthony Horgan brought Munster back to within seven points at 27-20 with 15 minutes left to play.
It was anyone's game at that stage, but Bowen kicked a penalty and then scampered over for a try in the last minute which he also converted.
The Celtic Warriors made it two out of two for Welsh clubs over Irish opposition with a superb 37-16 victory over the Leinster Lions at Donnybrook. Neil Jenkins was at it again with seven more successful goal kicks to make it 44 without a miss.
The Warriors ran in four tries to capture a bonus point, but it was the 17 points from the ever reliable boot of the world record points scorer that made the big difference.
Richard Mustoe, Sililo Martens, Shaun James and Jon Bryant grabbed the Warriors tries, while Argentinian international Felipe Contepomi scored all the Lions points.
Ospreys No 8 Nathan Bonner-Evans turned into a dragon slayer as he scored two tries to steer his side to a much needed 26-14 home win over Newport Gwent Dragons.
With league leaders Ulster going down to a shock defeat at Glasgow, victory would have taken the Dragons to the top of the Celtic League. Percy Montgomery kicked two penalties and Ben Breeze ran in a try to give the visitors' an 11-8 interval lead, but the Ospreys turned on the style after the break and Tongan international Dave Tiueti grabbed a third try and Gavin Henson ended with 11 points from the boot.
Wales reached their first semi-final since 2013 in the opening round of this season's HSBC World Rugby Sevens Series in Dubai. WRU TV's Graeme Gillespie recaps on what proved to be an eventful tournament
Wales and Ospreys back row James King, who came through the North Wales age grade system, nominated North Wales Regional Community Rugby Manager Marc Roberts, in the WRU's 'Diolch' initiative where squad players thanked those who played a part in their rise to the top.
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.
When the Wales squad were asked to nominate individuals who played a big part in their early playing days, Wales and Dragons full back and wing Hallam Amos thought of his former Monmouth School rugby coach John Bevan.
Sam Cross and Luke Treharne have been named as co-captains of the Wales Sevens side as head coach Gareth Williams names his 12-man squad to play in the first leg of the HSBC World Series in Dubai next weekend.
Bedwas head coach Steve Law and players Nicky Griffiths and Alun Rees extol the virtues of the close knit club as they prepare to host third place RGC 1404 - who are one place head of them on the Principality Premiership points table - on Saturday.
Many of the Wales squad have said Diolch (thank you) to someone who played an important part in their early playing days by nominating them to be invited to the Wales v South Africa match. One person, Gowerton Comprehensive geography teacher Mr Dean Mason was nominated by two of his former pupils, Dan Biggar and Sam Davies.
The second WRU disability rugby pilot has been delivered, this time in Caerphilly schools, culminating in a festival at the Caerphilly Centre of Sporting Excellence, Ystrad Mynach tomorrow. Plans are in place to set up a Disability Rugby Club in Newbridge to provide long-term playing opportunities.
WRU TV: Hear from inside the Wales camp as Neil Jenkins discusses this weekend's clash with South Africa and how the squad are looking to put in a strong performance to round of the 2016 Under Armour Series