The Scots open their Group D campaign with a trip to Dortmund on September 7 when Germany could be making their first competitive outing as World Cup winners, providing they beat Argentina at the Maracana Stadium this Sunday.
McCall, assistant to national manager Gordon Strachan, believes there would be no greater challenge for the Scotland team.
“Gordon’s been on about it for some time about how well they play, their mindset and we saw it the other night," he told Sky Sports News.
“Everyone’s been going on about Brazil, because they weren’t great, but Germany were fantastic. Everything about them, the movement, physicality, strength and, of course, the clinical finishing.
“I really enjoyed watching them and I was thinking ‘maybe one or two of them won’t be playing against us’, but who knows.
“We said when the fixtures were decided, there was a chance we could be facing the World Cup holders and I did tip a Germany v Argentina final.”
The other four countries in Group D are Republic of Ireland, Poland, Georgia and Gibraltar.