Tries from Tom Williams and James Davies helped Scarlets take control, helped by points from the boots of Williams, Dan Jones and Aled Thomas who split kicking duties.

Glasgow scored through a Pat MacArthur try and nine points from Rory Clegg. The 12-point victory lifted Scarlets up a place in the PRO12 standings and now three points clear of Warriors.

Scarlets oozed confidence on the back of winning nine of their last 10 PRO12 games while Glasgow looked fragile as the play-off challengers crashed to a third defeat in their past five matches.

The first try came after Clegg and Jones had traded a pair of early penalties and the Scarlets fly-half had been sent to the sin bin after a professional foul on Lee Jones.

With the extra man, Glasgow caught and drove an attacking lineout deep inside the Scarlets 22 and hooker MacArthur was there to touch down.

Clegg added the extra points but despite being a man down the Welshmen produced their best spell of the match and pulled a try back when Williams touched down in the corner. The winger added the conversion.

That score suddenly brought the game to life as Clegg and Jones again traded penalties before Davies struck a blow as the clock approached the 40-minute mark. A break out of defence by Jones created the position for Williams to set up flanker Davies to rush home in the corner. Jones converted.

At 20-11, it looked a hopeless task at the start of the second half for the hosts but another Clegg penalty within seven minutes of the restart pulled Glasgow within six points.

Scarlets, however, were not fazed, absorbing further Glasgow attacks before snuffing out a potential comeback.

Jones added his third penalty after 54 minutes and then Thomas wrapped up the scoring with three further points late on.