Months of speculation came to a head in the summer when the 35-year-old finally made his move to Old Trafford, penning a one-year deal with the option of a further 12 months.
Ibrahimovic, like the team as a whole, enjoyed an exceptional start to the campaign, only for that to tail off and leave United nine points off the lead after just 12 games.
The Swede always thought United would be "underdogs" and remains confident they can kick on, with Mourinho, his former boss at Inter Milan, as important in his move as the challenge itself.
"The team I signed for this summer is not as strong as the one I left, but when Mourinho called the decision was easy," he told Aftonbladet.
"When he calls I have no problem coming, all we had to decide was when I was to be presented as Man U player
The rest, the financial deal, was not the difficult part.
"It was about the challenge really, and I will never say no to a challenge.
"This is what I wanted; coming to one of the world's biggest clubs, that has had troubles and not won much of late, and try the Premier League
That is the challenge."
Ibrahimovic was speaking ahead of receiving his 11th Guldboll, the prize presented by Aftonbladet and the Swedish FA to the country's best player.
A statue of the 35-year-old in Stockholm is now in the offing, so too it appears is an eventual move to the United States.
Ibrahimovic has long been linked with a move to Major League Soccer and such a move clearly interests the striker.
"It's a huge option for me," he said
"For the football and everything else.
"I can see myself conquering the US as I have with Europe.
"Lots of people stay in one place throughout their career, but I've travelled around like Napoleon, and conquered every new country where I've sat foot.
"So perhaps I should do what Napoleon didn't and cross the Atlantic and conquer the States as well."
Source : PA
Source: PA