United were flying as the season entered its final two months with four successive wins and big names banished in the form of Spurs and Liverpool.
Sandwiched between the four games against top five opposition came a home game with Tim Sherwood's struggling but improving Aston Villa outfit.
The Reds were too strong for the Midlands side though, and won a fifth game on the bounce with a brace from Ander Herrers and a stunning goal from Rooney setting up a 3-1 success (Benteke with a late consolation for Villa).
The fixture list did not get any easier though for the Reds, as cross-town rivals and soon-to-be deposed champions Manchester City came to Old Trafford in search of a fifth successive derby win.
Sergio Aguero put them ahead to leave United fans fearing the worst, but the Reds stormed back to lead at half-time through goals from Ashley Young and Fellaini.
Juan Mata made it 3-1 and Chris Smalling headed in a fourth to put United and their fans into dreamland and not even Aguero's late second put the dampener on another hugely momentous win.
The Reds had leapfrogged City into third place with second in their sights, but United's magnificent run of form came to end on the 18th at champions elect Chelsea.
Van Gaal's side were brilliant and deserved a point, but Eden Hazard's solitary strike was
enough to win the game for Mourinho's side.
United end the month with an awful day on Merseyside as Everton take advantage of a lacklustre performance to win 3-0 at Goodison for the first back-to-back defeats under Van Gaal.
The Reds end April in fourth position, needing two wins from the last four games to seal a return to the Champions League for next season.
April: Played 4 Won 2 Lost 2 Goals For 7 Goals Against 6