Sale slumped to a 12th successive defeat in top-flight European competition as their Champions Cup campaign suffered an immediate setback at Parc-y-Scarlets.
The Sharks, without a European Cup win since they beat Cardiff Blues two years ago, were sent on their way by first-half tries from Scarlets scrum-half Gareth Davies and wing DTH van der Merwe.
And Van der Merwe's second touchdown after 57 minutes ended the contest, with Scarlets fly-half Rhys Patchell adding three penalties and two conversions to underpin a comfortable win before next Saturday's daunting assignment against Pool Three favourites Saracens in north London.
Hooker Neil Briggs claimed a try for the visitors, with fly-half Dan Mugford adding two penalties, but in a group that also includes European heavyweights Saracens and Toulon, Sale already look as if they will be making up the numbers.
The Sharks host Toulon in six days' time, with the French side on the rebound following their home defeat against opening opponents Saracens, so another tough encounter beckons.
Scarlets head coach Wayne Pivac fielded a side containing 11 internationals, with his resources bolstered by returning trio Jonathan Davies, Jake Ball and John Barclay, while Sale showed three changes from last week's heavy defeat against Bath as Mugford, full-back Mike Haley and prop Ross Harrison all started.
Mugford kicked Sale into a third-minute lead, but the Scarlets responded with a 13-point scoring burst in six minutes as they made their presence felt.
A Patchell penalty put them level, then Davies charged down Mugford's attempted clearance from just inside his own 22 and gathered the bounce to score, before Patchell converted and then kicked another penalty to leave Sale 13-3 behind.
Patchell then landed a long-range penalty, leaving Sale in considerable trouble early on, but they responded from their first attack as the forwards laid an imposing platform and Briggs stormed through a gap to touch down and reduce the deficit.
But the Scarlets continued to dominate territory and possession, and it came as no surprise when they extended their lead following more superb work by Wales number nine Davies.
He made initial headway with a searing burst, before his half-back partner Patchell kicked brilliantly towards the right wing, and Canada international Van der Merwe gathered and finished in one movement to restore a 13-point advantage.
Mugford applied the final scoring act of a lively opening period when he kicked a penalty just before the break, but the Scarlets were good value for a 21-11 interval advantage.
And Sale did not help their cause when they were temporarily reduced to 14 men just eight minutes after the restart when a reckless tackle by Harrison on Scarlets skipper Ken Owens resulted in French referee Romain Poite sin-binning the prop.
Van der Merwe's second try sealed the deal, and Sale then collected a second yellow card, this time for substitute Andrei Ostrikov following a high tackle, which left the closing 15 minutes all about whether or not the Scarlets could claim a bonus point.
It did not materialise, though, which was the only blot for them on an otherwise strong night's work that at least puts them in contention alongside Saracens and Toulon at this early stage.
