David Moyes’ much-changed side coped admirably with the absence of big names David De Gea, Rafael, Nemanja Vidic, Rio Ferdinand, Michael Carrick, Wayne Rooney and Danny Welbeck to avenge December's 1-0 defeat at Old Trafford.
Mata’s first strike was a devilish free-kick and the second the cheekiest of finishes after good work from Shinji Kagawa and Hernandez. The excellent Kagawa set up Chicharito, who hit a post in the first half, for a predatory prod past Rob Elliot to prompt some disgruntled home fans to leave the ground with 20 minutes still remaining.
Anders Linedgaard made three wonderful saves to deny Papiss Cisse - the final stop truly astounding when a goal seemed certain - to keep a clean sheet that he will cherish on a rare start. Januzaj also sparkled after coming on for Ashley Young, who was taken to hospital with a thumb injury, and added a fourth in stoppage time following a delightful one-two with Mata, setting United up nicely for the midweek mission in Munich.