The Red Devils had defeated Alan Pardew's Crystal Palace in the final at the Wembley Stadium after conceding a goal first.
Jason Puncheon had scored the opening goal in the 78th minute, but Juan Mata equalised within 3 minutes. Jese Lingard netted the winning goal in the extra time to gift Louis van Gaal his only trophy at Old Trafford.
Even though, managers do not pay much heed to the FA Cup nowadays as they have several other important tournaments to concentrate, Van Gaal considers the trophy to be his biggest prize ever.
Speaking about the FA Cup triumph, the Dutch manager insisted that the kind of pressure he was in, in the last 6 months at the club, the FA Cup came as a gush of fresh air.
Manchester United were failing miserably under the tutelage of the famous manager at it was almost two years.
The fans were furious, the officials were disappointed and the media wanted a piece of the manager. He even had a fall-out with the local media during the New Year.
Thus, the manager who had won several accolades at various big clubs, considered FA Cup to be his biggest achievement.
Addressing the media at a press conference in Holland, Louis van Gaal said: "The last six months at United, the circumstances, were so difficult. That is why the trophy I won, the FA Cup, I consider the biggest trophy in my career.
"When they have put you on a stage with your head on the block, my head was in a noose for six months with the English media on top of me.
"Under those circumstances, I was expected to inspire those United players every day.
"Going to the absolute climax of the FA Cup Final, ending with ten men and having to score to win In extra-time. Having gone through all that, and then walking away with the trophy, was incredible for me.
"I've had lots of offers since including millions from China. They are prepared to pay a fortune."
After the season, the Dutchman resigned from his post on mutual consent and Jose Mourinho replaced him at the helm of affairs at Old Trafford.