Davies, the late try hero in the epic late win over defending champions Toulon in round two, comes into the starting line-up as Davies makes just one change to his side.
Rhys Patchell, who scored a try in the closely fought 29-20 win when the teams met last week, moves to inside centre with Dafydd Hewitt ruled out with a shoulder problem.
Lock James Down and back row Andries Pretorius are called onto the replacements bench.
Davies said: "We were pleased with the motivation and spirit we showed last week. We have been getting better all year and at the moment, the performance levels are growing.
"We will need to work even harder up in Scotland. We need to go up a level physically and tactically and be more accurate with the ball. Last week was about desire and performance, this week we need to extract even more from the players."
He added: "I expect Glasgow to play like men possessed. We looked to play a certain way last week against them and executed it.
"But we know how good they can be and have had some terrific games up there. Friday will be no different.
"The team that controls the ball in the opposition attacking third will be hard to beat. It's a tough game because they will have been disappointed by last week, but we need to build on what we have achieved in this competition."