Well, who saw that coming? Even the most optimistic Milanisti couldn't have genuinely thought the Rossoneri would not only win by two great goals, but would also look so comfortable doing it.
This imperious performance at the San Siro has made all of world football take notice, and Massimiliano Allegri's men have sent out a clear message: AC Milan are back.
With strikes from Kevin-Prince Boateng and Sulley Muntari, Serie A's giant of the European stage showed that it has the composure and the class to challenge for top honours and possibly even add to their seven Champions League titles.
So what did we learn from the first leg of this tie?