Brandon Thomson scored 24 points as he helped steer Glasgow to a valuable win

Warriors lost prop Alex Allan to a red card for a dangerous tackle in the first half of the PRO14 clash but a try by Glasgow fly-half Brandon Thomson plus the conversion and two penalties by the same player against a Rhys Patchell penalty saw Warriors lead 13-3 at half-time.

In the second half Scarlets touched down through Jonathan Davies, Steff Evans and Clayton Blommetjies, which Patchell converted.

But they were always trailing Glasgow - who remain out in front in Conference A - for whom Thomson went on to kick three penalties plus the conversion of Nick Grigg's try.

"The red card probably galvanised us, we worked really hard for each other," Head Coach Dave Rennie told BBC Scotland after the game.

"We believed that even with 14 guys we could do the job but we needed to hang on to the ball for long periods.

"We were really composed and asked lots of questions and were eventually rewarded with penalties that we either took field position from, or points.

"Our scrum was great. Our big men were outstanding. Post-tackle we were really strong and our ability to look after the ball was really good.

"We were always going to be under pressure if they went wide but we scrambled well. It was disappointing to let in a couple of soft tries late but we had massive heart."

Allan was dismissed by referee Frank Murphy after a review of his challenge on Jake Ball, with the Scarlets lock forced off after the knock to his head.

The home fans were incensed by the decision but Rennie was more phlegmatic in his assessment.

"That's the way it is now," he said. "If you catch someone high and get them with a shoulder, you bring the referee and TMO into the game.

"We've seen examples of red cards and some have been let go.

"As long as they are consistent, I'm okay with that. It's an area of the game that we need to tidy up, so we need to be tough."

Glasgow visit Lyon in the Champions Cup next weekend, with Rennie able to recall the international stars that were rested after the autumn Test series.

However, the New Zealander suggested he may have to rethink his strategy after so many impressive performances from his fringe men.

"We talked about the fact that regardless of who is playing that there is an expectation that you front," he said.

"There is good pressure on the guys coming back and some of the guys from tonight will be rewarded. We've got some tough decisions to make on Monday.

"We are creating depth and competition and that is important."