Gregor Hayter went over for Glasgow's try

Tries from Hottie Louw and debut-making scrum-half Liam Davies, plus effective kicking from Gareth Bowen, put the home side comfortably in control at 21-9.

But Gregor Hayter was let in for a soft 51st-minute try and from then on it was all Glasgow, Dan Parks' 15 points putting them within a score of victory.

The Scarlets held on, Glasgow taking a bonus point but seeing Andrew Wilson carried off with a suspected leg break.

The early exchanges seemed a softening-up process, with the Scarlets dominating territory and possession and Bowen rattling up the points from three resultant penalties.

Glasgow fly-half Parks replied with two penalties of his own, though, to keep his side in touch.

But under the continual pressure the visitors' scrum-half Sam Pinder was yellow carded.

The Scarlets kicked to the corner, and from a scrum near the Warriors' line Springbok lock Louw ploughed over for his first try for the Llanelli side.

That made it 16-6, and to compound Glasgow's woes flanker Wilson was stretchered off on the stroke of half-time.

Parks landed another penalty early in the second half, but after a sustained Scarlets attack Davies broke swiftly down the blind-side and had the speed to cross for the second try.

Glasgow replacement Hayter then hit the Scarlets with a shock score, taking short ball from a line-out on their 22 and brushing aside Matthew Rees' weak tackle for an unopposed run-in.

Another Parks penalty cut the gap to just three points, as the Scots staged an inspiring fightback.

Garan Evans made his first appearance of the season in place of Lee Byrne, whose shoulder injury could make him doubtful for the Toulouse game.

Bowen and Parks exchanged penalties, and the Scarlets held off the Warriors' last desperate attacks.

To compound Glasgow's woes, Rory Lamont limped off in the last minute and could be doubtful for Friday's game in Bourgoin.

Report from BBC Sport