United, who led by a whopping five goals after the first leg in Linz, went behind to a stunning strike from LASK defender Philipp Wiesinger early in the second half, but responded decisively via goals from Jesse Lingard and Anthony Martial.
That means we'll now travel to Cologne to battle FC Copenhagen on Monday, for a place in the semi-finals.
The manager spoke to both BT Sport and club media after the final whistle at Old Trafford, and discussed a first senior appearance for promising young defender Teden Mengi and also revealed what he said to match-winner Anthony Martial before sending on the striker in the final stages.