Scarlets 16 Glasgow 14
A Gareth Davies try and 11 points from Rhys Priestland were just enough for the Scarlets as they registered their third consecutive RaboDirect Pro12 victory at Parc y Scarlets.
The home side were well below par against an under-strength Glasgow, who earned a losing bonus point for their efforts.
The Scarlets fielded 11 changes from their 10-6 win at the Dragons. They included an impressive backline boasting internationals George North, Sean Lamont, Jonathan Davies and Scott Williams.
They also picked Ben Morgan at number eight in his first game since deciding to opt for England rather than Wales.
Glasgow arrived with a weakened team minus the likes of Ali Kellock, Richie Gray and John Barclay.
But despite that the Scarlets were hit by an early try. A Scarlets line-out went awry close to their line and prop Moray Low pounced for the score.
Outside-halves Priestland and Ruaridh Jackson swapped penalties, but after kicking his Jackson had to be helped off with a hamstring injury.
Priestland’s second penalty on 16 minutes cut Glasgow’s early lead to 8-6.
And as Glasgow went off side Priestland kicked a third on 24 minutes as the Scarlets went into the lead for the first time.
Glasgow suffered two setbacks in the space of a minute when flanker Rob Harley (punch) and No. 8 Ryan Wilson (professional foul) found themselves yellow-carded by referee Dudley Phillips.
And down to 13 men Glasgow conceded a converted try deep into injury-time with scrum-half Gareth Davies nipping over to give the home side a 16-8 interval lead.
Glasgow showed much more urgency after the break and earned a penalty kicked by Scott Wight on 44 minutes.
The Scarlets needed a change and brought on the experience of Stephen Jones on to steady the ship and he made an impact as both Jonathan Davies and North made surges towards the Glasgow line.
But a second try proved elusive as Glasgow cut the deficit to just a point with a second Wight penalty on 70 minutes.
The Scarlets pressured the Glasgow line and thought they had a try but the referee disallowed it for a knock-on leaving the home side pointless in the second half