But Gordon Strachan’s assistant insists Wednesday’s friendly will have little bearing on Sunday’s Hampden clash.
Strachan claimed the 1-1 draw provided “invaluable” information as he admitted some players could not rise to the challenge of playing international football on a difficult pitch after a lack of game time with their clubs.
And McGhee said on Thursday: “The team will change. If we were sitting here saying the team that we had last night is the same team that’s going to play on Sunday night, and therefore the manager has to come up with some story to convince them that they are going to do better on Sunday night than they did last night, then I tell you what, I would be worried.
“But that is not the case. It’s a totally different thing Sunday night and we feel pretty positive about it.”
The likes of Chris Martin and Oliver Burke made the line-up against the Canadians after starting few games for their clubs in recent weeks, while Fulham midfielder Tom Cairney impressed on his debut.
McGhee said: “Last night didn’t really bear a lot of relation to Sunday night. It was an exercise in something else: one or two people getting games; Tom getting a start and introducing him to people.
“So I don’t really feel there was much that I saw that is relative to Sunday.
“We have known all along the importance of Sunday night and have a totally different way of thinking about Sunday than we did last night.
“I don’t mean we will take it more seriously but last night was a totally different exercise. What happened last night was totally irrelevant to Sunday night.”