The Australian international midfielder made his second appearance for the Scottish champions who triumphed at Ibrox and his showing was not lost on McCoist.
"Matt McKay did really well and could have scored with a header in the first half," the 'Gers boss told the club's official website.
"His positional sense is very good and he has obviously been coached well because his movement on the left hand side is very good.
"He came inside at times and that allowed Lee Wallace to get wide and put some good balls in."
Former Brisbane Roar captain McKay will now go into McCoist's plans for Sunday's league clash with Heart of Midlothian at Tynecastle and will be hoping to add to his only other appearance which was a six-minute cameo against Dundee United on September 10.