United were among several top clubs represented at the Parken Stadium in Copenhagen for Tuesday night's World Cup qualifier with Everton, Hamburg, Wolfsburg, Ajax and Borussia Dortmund also in attendance.
Cornelius, 20, is the new golden boy of Danish football after an outstanding season in which he scored 18 league goals and five for his country.
But he, alongside all his teammates, failed to impress as Denmark's last hopes of qualifying for Brazil 2014 were all but extinguished by a clinical Armenia side who were smarting from last week's 1-0 home defeat to Malta.
Liverpool target Henrikh Mkhitaryan was one of the stars of the show, scoring Armenia's fourth goal, but the Merseyside club did not officially send a scout to the game.
United also have scouts in Israel for the European Under-21 Championships and last night saw a dramatic late equaliser from Andrea Bertolacci deny Norway top spot in Group A.
Both nations fielded weakened sides for the match in Tel Aviv because they were already guaranteed their places in the semi-finals.