They ran in four tries in their convincing win over the Dragons at Parc y Scarlets while Blues North were narrow winners over the Ospreys.
Fullback Jack Evans was the star for the Scarlets, contributing 17 points.
On a dry but breezy evening, the Scarlets played into the wind in the first half although it mattered for little as they soon opened up an advantage.
From the start, the Scarlets combined error free rugby with great composure both with and without the ball as they ran out convincing 32-0 winners.
It took just seven minutes for the home side to open the scoring, prop Richard Bassett crashing over after the Scarlets forwards had given them territory inside the opposition half.
Evans converted and then added a try of his own. From a scrum near the halfway line, the Scarlets’ backs moved the ball wide with the fullback using his pace to cross under the posts.
The Dragons battled hard but could not match the Scarlets’ enthusiasm to play running rugby and further scores from Billy McBryde and Kieran Jones added gloss to an easy win.
At Abercynon, Blues North were 20-18 winners over the Ospreys.
The home side outscored their visitors by three tries to two but were only narrow winners.
Leon Rogers, Gerwyn Coleman and Jarred Evans all scored for the Blues with Owen Watkin and replacement James Taylor going over for the Ospreys.
Rogers opened the scoring in just the second minute with fly-half Callum Hall adding the conversion and a penalty to put the Blues 10-0 up.
Scrumhalf Matthew Aubrey kicked a penalty for the Ospreys before hooker Coleman extended the Blues lead with a 41st minute try.
Aubrey kicked another penalty after half-time before Evans added a try of his own. With a 20-6 lead, it looked like being an easy win for the Blues but tries from Watkin and Taylor made sure it was a nervy ending for the home side.
