The fly-half scored a second-half try and kicked 16 points as Steve Diamond's men kept alive their hopes of reaching the knockout stages of the Anglo-Welsh tournament.
Sale have endured a bitterly disappointing Aviva Premiership campaign and lie bottom of the table after 13 games.
But they ultimately had too much power for their Welsh visitors as tries from Richie Vernon, Charlie Amesbury, Cipriani and replacement Charlie Ingall secured the win.
The Scarlets, missing over 20 first-team players largely due to international commitments, opened the scoring in the fourth minute after Cipriani misjudged a bouncing ball and Andy Fenby hacked forward before touching down.
Owen Williams added the conversion but the visitors began to concede a number of penalties, giving Sale vital field position, and one fine rolling maul had the home supporters roaring their approval.
Moments later Sale skipper David Seymour was replaced by James Doyle but Sale's period of pressure eventually told as Cipriani landed a penalty from 35 metres to get them off the mark.
The response from the Scarlets was highly impressive, however, and they enjoyed a period of pressure which covered several phases.
Midway through the opening period, they were finally rewarded when Williams embarked on a fine break down the right flank before sending scrum-half Gareth Davies clear.
Williams converted in style to put the Scarlets 14-3 ahead but Sale quickly ploughed upfield and Amesbury's determined run led to the visitors conceding a penalty which Cipriani converted from underneath the posts.
Vernon then went close in the right corner before some fine defending kept him at bay.
Moments later Scarlets forward Jake Ball was sin-binned and the visitors' 14 men were soon punished when Vernon burrowed over from close range to level the scores at 14-14.
Cipriani failed to add the conversion but right on the stroke of half-time Sale engineered a fine sequence which culminated in Amesbury plunging over in the left corner for a second home try.
Cipriani converted his fourth shot at goal from five attempts to leave Sale 21-14 ahead at half-time but the visitors replied with another penalty from Williams after the break.
Cipriani then hit back with another penalty for Sale and the Scarlets had Rhodri Jones sin-binned before Cipriani raced over the line after spotting a gap in the 63rd minute.
He added the extras to his own try, and then Ingall went over in the left corner with six minutes remaining for a try which this time Cipriani could not convert.
- Sports & Recreation
- Charlie Amesbury
- Richie Vernon