Outside-half James Hook scored a splendid solo try and converted as well as converting tries by wings Richard Johnston and Aled Brew and slotting four penalties in a 23-point haul.
Newport kept in touch with a convincing 43-13 win over Carmarthen Quins. A brace of tries from centre Richard Payne sent the Black and Ambers on their way while Quins' centre Emyr Jones grabbed his 100th league try as a late consolation.
Caerphilly finally lost their fight to avoid relegation as they went down to 14-man Llandovery at Virginia Park despite visiting prop Andrew Jones getting his marching orders midway through the second half.
Gareth Thomas and Tom Hearne scored late on but it was not enough to save Caerphilly from the drop and a 41-24 loss with Gareth Morgan kicking seven goals for the Drovers.
Bridgend came from behind to beat Swansea 21-14 at St Helen's thanks to second-half tries by Brendan Roach and Ryan Howells after Rhodri Wells had put the All Whites ahead.
Wing Darren Berry helped himself to a hat-trick as Pontypridd staged a stunning turn around to smash Bedwas 71-5 just three days after losing to the same opposition.
Pontypridd's cup semi-final opponents Aberavon warmed up for next Saturday's clash with a surprisingly convincing 43-15 win over Cross Keys with influential No 8 Richard Morris going over for two of the six tries by the Wizards.
Ebbw Vale crossed Llanharan's line four times in their 31-12 success at Eugene Cross Park after the visitors had led at the interval.
The last five years have been an emotional rollercoaster on and off the pitch for RGC1404. Promotion to the Principality Premiership was the culmination of five years of hard work and investment in North Wales. WRU TV caught up with prop Joe Simpson, who was one of the first intake of WRU North Wales Academy players in 2010.
Ebbw Vale captain Damien Hudd picked up the biggest accolade of the night at the 11th Principality Premiership Awards Evening held at Principality Stadium, after leading his side to the title for the first time.
Wales assistant coach Robin McBryde is predicting a tough battle against England on Sunday despite the fact they may not be considered to be at full strength. Players will be out to impress Eddie Jones which makes England a dangerous proposition, he says.
Wales U20 captain Tom Phillips and performance psychologist Dr Rich Neil explain why spending three days at Monmouth RFC has further strengthened the togetherness of the squad ahead of the #WorldRugbyU20s