England flanker Hendre Fourie scored a home debut try as he inspired Sale to victory but Scarlets still progress to the LV= Cup semi-finals.
Scarlets' bonus point, plus defeats for pool rivals Gloucester and Newcastle, earned them a last four spot.
Sale fly-half Nick Macleod kicked 14 points and Fourie capped a superb debut with a try from a drive from a lineout to earn a first Sharks LV= Cup win.
Prop Peter Edwards scored Scarlets' reply from Andy Fenby's pass.
But the Welsh region finished five points clear of Gloucester in Pool Three to at Franklin's Gardens.
Sale Sharks: Miller; Brady; Leota, Tuitupou; Tuculet; MacLeod, Peel; Cobilas, Jones, Buckley, Lewaravu, Ostrikov, Auva'a, Fourie, Easter.
Replacements: Burrell for Tuitupou (77), Amesbury for Tuculet (59), Willis for Peel (58), Ward for Jones (59). Not Used: Imiolek, Harrison, Myall, Taylor.
Scarlets: Newton; Iongi; Maule, Warren; Fenby, A Thomas, G. Davies; John, Phillips, P Edwards, Timani, Welch, Gilbert, J Edwards, Murphy.
Replacements: L Williams for Iongi (48), S Jones for A Thomas (55), L Davies for G Davies (65), R Jones for John (52), Manu for P Edwards (55), Shingler for Timani (61), Reed for Welch (43). Not Used: Hawkins.
Referee: Martin Fox (RFU).