A try just before half-time changed the Scarlets fortunes and knocked Glasgow’s dominance up to that point, ending a run of five league victories and seriously denting their top two challenge.
There was illness in the build up through Covid and separate illness on the day with internationals Sam Johnson, Fraser Brown and Jack Dempsey all visibly sick, but coach Danny Wilson was keen not to use that as an excuse for the second half.
“I’m still trying to work out what happened a little bit,” admitted Wilson after the game. “It was not like us, we have gone well recently and it was a second half collapse.
“There was poor execution in the second half combined with good play from the Scarlets, along with illness and injury with having to make a whole host of changes.
“The week has led to that a little bit but we felt in the first half we were in control but did not get enough points for the pressure we had before half time.”
Glasgow’s forwards got an early edge and rubbed that in with a powerful lineout drive for hooker Johnny Matthews to get the try, converted by Duncan Weir.
They then held out the Scarlets forwards on their own line to make an early double point for the visitors.
That amount of pressure meant it was not long before they earned another kickable penalty. This time they chose to extend their lead through the reliable boot of outside half Duncan Weir.
So it all came as something as a surprise when it was the Scarlets who had the last word in the first half, scoring a try which came very much against the run of play.
A turnover brought the position and a neat lineout move saw scrum half Gareth Davies released with blindside wing Steff Hughes in support to go under the posts for the try. Rhys Patchell added the easy conversion.
Worse was to follow for Glasgow at the start of the second half as the Scarlets started to find space out side, flanker Dan Davis showing good footwork to put Evans clear on the left, with his pass back inside bringing a try for supporting centre Scott Williams.
Glasgow were not getting the break either, in particular when they appeared to have retaken the lead through scrum half Jamie Dobie from a break by full back Ollie Smith.
An outstretched arm by Glasgow back rower Ryan Wilson which did not seem to particularly affect Scarlets and Scotland opposite number Blade Thomson, however it resulted in the try being disallowed for a Scarlets penalty.
Patchell put the ball into the corner and scrum half Gareth Davies sidestepped his way over from the resulting lineout as the Scarlets went from potentially trailing to taking a firm grip.
The Scarlets grabbed their bonus point try through No 8 Sione Kalamafoni finishing of an attractive move , another knock on turnover gave the scarlets a fifth try against a much re-organised Glasgow back line, wing Ryan Conbeer finishing off.