In their Boxing Day game with fellow Welsh side Ospreys, the Llanelli-based side ran up a 44-0 win. It was the Scarlets 10th consecutive win over their neighbours and the 12th win in 13 matches this season.
The Ospreys' poor form has seen them drop below Italian side Zebre on points difference in their Conference.
Ospreys captain, and Wales international, Justin Tipuric said the loss had been embarrassing. It was their biggest loss and they hadn't scored a point, he said.
It doesn't help that his side is without a head coach and that their injury list includes British & Irish Lions and Wales stars lock Alun Wyn Jones and wing George North.
But that was not an excuse, he said.
"It was definitely the worst night in an Ospreys shirt by far.
"There are injuries, confidence issues, and no head coach so as you can imagine it's a lot of things.
"But you have got to show character and wear this shirt with more pride than we did tonight. Losing to our local rivals adds to it and probably tops it off.
"It's a tough place when you are down the bottom of the league. We have got to show a lot of character and keep working hard. Hopefully we can work our way out of it," he said.
In another Welsh derby, Cardiff Blues beat Newport Dragons 16-12 at Cardiff Arms Park.
Weekend action in England starts on Friday when Bristol host Wasps. On Saturday, Northampton will be looking to get their season back on track at home against Gloucester.
Bath will host Sharks and Worcester are at home to London Irish while Harlequins host Leicester. The last game of the weekend sees Exeter host Saracens.