The Armenia international was amongst the goalscorers as Jose Mourinho's men coasted into the fifth round of the competition
Henrikh Mkhitaryan praised Manchester United for eventually finding some fluency to down Wigan Athletic 4-0 in the fourth round of the FA Cup.
The holders put in a laboured showing during the first half, with former Borussia Dortmund star Mkhitaryan guilty of a terrible miss, but Marouane Fellaini settled any nerves with a headed opener in the 44th minute.
Anthony Martial crossed for Chris Smalling to make it 2-0 and the France international was involved once more, with United clicking sublimely through the gears, Mkhitaryan adding a third with 15 minutes remaining.