Marcus Rashford and Memphis Depay were the stars of the show as Manchester United booked their place in the last-16 of the Europa League.
Pione Sisto scored the opener on the night for FC Midtjylland, but Nikolay Bodurov's own goal reduced the deficit just five minutes later.
Rashford struck twice within 12 minutes to put the home side ahead on aggregate, and Ander Herrera's penalty and Memphis Depay's late goal completed the victory.
Juan Mata missed a penalty on the stroke of half-time, when the score was at 1-1, and the visitors ended the game with 10-men after Andre Romer was sent off for a second bookable offence.
United's woeful display against Midtjylland in the first-leg was certainly put behind them, read how each of the players got on in the return leg at Old Trafford.
Back five stand tall in make-shift defence
Sergio Romero (6 out of 10) - David De Gea may be back in goal for Sunday's visit of Arsenal, and the Argentine keeper may well have done a little better about Sisto's goal, however, he wasn't troubled at all for the rest of the game.
Guillermo Varela (7 out of 10) - Came out the blocks like a house on fire, Varela was straight at Midtjylland from the start, enjoying spells going forward down the right and produced some good crosses.
Michael Carrick (6 out of 10) - Brought in at centre-half due to the number of injuries at the moment and was at fault for over committing himself for Sisto's goal.
Daley Blind (6 out of 10) - Just like Carrick, Blind was partly to blame for Sisto's goal, following his attempt to close the forward down, however, he has been United's stand-out performer in recent games.
Joe Riley (6 out of 10) - Riley was gifted his full first-term debut due to the number of injuries, and it was an evening to remember after the youngster showed composure on the ball and pace as he got forward, didn't put a foot wrong.
Duo another class in centre of park
Ander Herrera (7 out of 10) - Herrera showed his worth for the second game running in the centre of the park, won a penalty and also scored one of his own late on. This may be the start of a good run in the side now.
Morgan Schneiderlin (7 out of 10) - Schneiderlin is a player that United have craved for many a year now, he was solid in the midfield and provided a goal threat going forward, and he also hit the post in the first-half.
Five-star display from forwards
Jesse Lingard (7 out of 10) - Lingard was resilient going forward, keeping his opponents on their toes all evening. Another promising display from the youngster as he is beginning to be one of the first names on van Gaal's teamsheet.
Juan Mata (6 out of 10) - If United hadn't of went on to rout their opponents, the talking point would have been the missed penalty from the Spanish international. His penalty was easily saved, but he redeemed himself by setting up the second goal.
Memphis Depay (9 out of 10) - A night to remember for the Dutchman that is for sure. Memphis finally stepped up to the plate on a big occasion. He set up the first goal, helped win two penalties and scored the final goal of five on the night.
Marcus Rashford (9 out of 10) - For someone that only found out 10 minutes before the game that they were starting, it was a dream debut for the youngster. Anthony Martial picked up an injury in the warm-up and Rashford scored a brilliant brace in the space of 12 minutes.
Substitutes
Marcos Rojo (6 out of 10) - Replaced Joe Riley for the final 11 minutes of the game, it was Rojo's first game in 2016 since his lengthy lay-off with injury, and was fairly untroubled for the closing stages of the game.
Andreas Pereira (6 out of 10) - A short appearance from the Brazilian, played the final four minutes after coming on for Jesse Lingard, came close to scoring in injury-time with a whipped shot from the edge of the box.
Regan Poole (5 out of 10) - Made his first-team debut in the closing minutes in place of Ander Herrera, didn't have enough time to make an impact on the game as such.