The 27-year-old attacking midfielder replaced Juan Mata late in United's 3-1 win in their Premier League season opener to become the first Armenian to play in England's top flight.
Mkhitaryan, who joined the Red Devils from German club Borussia Dortmund, also took the number of nationalities to have played in the Premier League to a remarkable 112.
1 - @HenrikhMkh is the first Armenian player to play in the @premierleague, meaning 112 different nations have now been represented. New.
— OptaJoe (@OptaJoe) August 14, 2016