The United boss barely raised a smile after Zlatan Ibrahimovic's late header earned him his first title at Old Trafford.
Arsenal legend Ian Wright wondered whether Mourinho had received bad news.
But the Portuguese coach said the win was for the United supporters, not him.
EPA
Manchester United's Jose Mourinho lifts the League Cup
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He said: "It's for them, it's for the fans.
"I take this because I've won it four times. I take this for me.
"It's the first one plus the Charity Shield.
"For the development of the team, there's nothing better than doing it with the feeling of trophies.