England flanker Hendre Fourie scored a try on his home debut to give Sale a 19-14 victory - but Scarlets were still able to progress to the semi-finals of the LV= Cup.
Scarlets' bonus point, coupled with defeats for their pool rivals Gloucester and Newcastle, guaranteed their passage into the last four. However, they will need to improve on their performance in the semi-finals, after being on the back foot for most of this match.
Welsh fly-half Nick Macleod kicked 14 points against his compatriots, while Fourie had an outstanding game on his first match at Edgeley Park since his move from Leeds in the summer. Peter Edwards scored the Scarlets' only try of the game.