Wales international backrower Dafydd Jones scored two first-half tries as a red-hot Llanelli marched into a mouth-watering Principality Cup semi-final against Cardiff at the Millennium Stadium in a fortnight.
The Scarlets hammered Neath 49-17 at Stradey Park after leading 22-10 at the break thanks to a last-minute 70-metre runaway try to centre Matthew Watkins.
Fullback Barrie Davies scored early in the second half, Watkins added his second and 19 points from the boot of Stephen Jones put the resultbeyond doubt.
The only black point for Llanelli was the suspected concussion suffered by talismanic No 8 Scott Quinnell, which puts him in doubt for next weekend's Heineken Cup quarter-final against Perpignan.
Llanelli: Tries - D Jones 2, M Watkins 2, B Davies, G Evans; Cons - S
Jones 5; Pens - S Jones 3.
Neath: Tries - G Morris, D Tiueti; Cons - S Connor 2; Pen - S Connor.
Halftime: Llanelli 22-10.