The 24-year-old Keatley kicked 13 points, including three penalties and two conversions, as the Red Army cruised to an unprecedented twelfth successive league win on Friday night.
Niall Ronan burrowed his way over in the first half and Simon Zebo touched down five minutes after the turnaround to effectively seal the points.
And while Glasgow did rally with a couple of Duncan Weir penalties it was Keatley who McGahan singled out for special praise in the absence of main-man Ronan O'Gara.
"Ian was a tremendous leader for us," he said. "He defended really well, kicked well out of hand and ran the ship. He's more comfortable with the group, and that's evident in his play.
"They're getting more comfortable playing with him too and understanding what he's capable of doing because he's certainly getting a bend in the defensive line and creating opportunities for others to run off him.
"He's a real threat with the ball in hand as well as a threat with passes and kicks, so he's a real danger around that channel."
In yet more good news for the defending champions, they also announced the signing of centre Will Chambers from Queensland Reds on a short-term deal.
And McGahan admitted that he was already looking forward to seeing what the 23-year-old will offer on the pitch.
"Will brings a lot of experience," he added. "He's already won a Grand Final in the NRL and a Super 15 title."
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