Goals from Paul Pogba and Henrikh Mkhitaryan secured a 2-0 victory over Ajax in Stockholm on Wednesday night and earned more silverware for the club following victories in the EFL Cup and the Community Shield.
Mourinho’s first season in charge yielded only a sixth-place finish in the Premier League, but Wednesday night’s win secures a place in next season’s Champions League – and Mourinho insists the season must now be seen as a success.
He said: “In a bad season, in a season where sometimes I felt that my team was the worst team in the world, where I felt that sometimes I was the worst manager in the world we managed to win three trophies and we go to the Champions League by winning a trophy, not by finishing second or third or fourth.
“We have the honour to go to the European Super Cup and play against the new Champions League winner, so I think the season was really good.
“Tonight was the victory of pragmatism, the victory of the humble people, the people that respect opponents, the people that tried to stop the opponents’ qualities, tried to exploit the opponents’ weaknesses.
“For me, it was a victory of a fantastic group, but based on pragmatism and based on humble principles. No poets, just humble people.”
Mourinho has previously won the Champions League with Porto and Inter Milan as well as claiming league titles in England, Spain and Italy. But he says this Europa League win with United feels like his biggest ever success.
“For me, it is the most important trophy of my career because it is the last. That’s the way I look at things,” he added.
“Of course, Champions League is bigger than Europa League, but that’s the last trophy and the last trophy is the one where the feelings are under the skin.
“It is obviously a fantastic feeling.”