Both sides had won their first games easily so this game was likely to be key at the end of the regional season.
The Scarlets started the strongest but some poor passing allowed the Blues into the game and they ended the first half the strongest with only committed try line defence led by Jodie Williams, Ffion Jones and Emily Coleman keeping out a strong Blues attack.
The second half started like the first with the Scarlets in control but after the break the Scarlets seemed to have a new resolve, and when the ball was moved quickly wide to Sioned Jones, she beat two defenders on the outside to score near the corner flag.
With the conversion attempt wide of the mark, the result was still in the balance and despite the Scarlets dominating possession the Blues backline looked dangerous every time they had the ball, but determined defence from the Scarlets stopped every attack from the Blues.
The last 10 minutes of the game was a battle of wills, but the Scarlets were determined after last season's 0-0 score line not to let their lead slip.
With Chloe Davies and Elisha Butchers winning the breakdown battle and no gaps in the Scarlets backline defence, the Blues had nothing left to offer, and the Scarlets held on for a deserved victory.
With only one try conceded in 10 regional games, the Scarlets defence proved to be rock solid.