Cardiff Blues lost their stranglehold over Ulster, which stretched back seven games to October, 2006, as they were beaten 37-15 at home in the Magners League.
The Blues were leading 15-8 at the break thanks to tries from Casey Laulala and Tom James, but then fell apart in the second half as they conceded four tries and 29 unanswered points.
Ulster's teenage wing Craig Gilroy scored a try in each half and his second touchdown, which began at a quickly taken line-out in the visitors' 22, turned the game on its head.
It also came in the middle of a 15 point burst from Ulster in the space of four minutes and set them on their way to a first bonus point victory of the season.
The defeat means the Blues lose their grip on third place in the Magners League table, Ulster moving ahead of them, and puts added pressure on next weekend's home clash with Glasgow Warriors.
Earlier in the weekend a last gasp try from replacement scrum half Jamie Nutbrown earned the Ospreys an important 16-15 victory over Connacht in Galwey. That triumph included a drop goal from the 18-year-old Matthew Morgan on his Magners League debut.
But there wasn't any luck for the Dragons in Ireland as they conceded four tries in a 27-6 defeat against Leinster in Dublin.
Wales Head Coach Rob Howley talks to WRU TV's Sebastian Barrett about the 36-man squad he has just named for the forthcoming Under Armour series, which includes two uncapped players, Ospreys duo Sam Davies and Rory Thornton.
Head coach Rowland Phillips is deligthed he can now call BT Sport Cardiff Arms Park home for his Wales Women's side, who launch their international season next month with games against Scotland and UK Armed Forces in the heart of the capital city.
Wales Sevens star Sam Cross has put his home town club of Brynmawr on the map after winning a silver medal at the Rio Olympics with Team GB. His club have now honoured him by naming their players bar after him, as WRU TV discovered at the official launch, recently.
One of the newest members of the Principality Premiership, Bargoed admit it's proving to be a steep learning curve at the highest level, but are determined to become a force to be reckoned with. WRU TV visited the club last weekend when they took on Llanelli.
Table-topping Aberavon travel to north Wales to tackle RGC 1404 as both teams defend unbeaten starts to the season in the Principality Premiership. WRU TV's Graeme Gillespie visited the Wizards to see how their preparations were going for the game of the weekend.
The Half a Game initiative is currently sweeping across Wales and proving a major success. The scheme aims to give every young player at least half a game every weekend. WRU TV recently visited a festival in Narberth where clubs have fully embraced the initiative.
Both Bargoed and Swansea were seeking their first win of the Principality Premiership season this afternoon. It proved a fruitful day for the hosts - not only did they win, but Bargoed claimed a try bonus point.
Cardiff managed to keep their unbeaten record at home intact, but only just as Bridgend made them work extremely hard before the Blue and Blacks secured a hard fought Principality Premiership win at the BT Sport Arms Park last night.
Former Wales back row Andy Powell gives a guided tour of The Wern, home of Merthyr RFC, who are determined to prove a lot of people wrong and make their mark in their first season in the Principality Premiership.