Ibrahimovic appeared as a 77th-minute substitute as Jose Mourinho’s side ran out 4-1 winners over Newcastle at Old Trafford.
Zlatan Ibrahimovicclaims his knee problems were far worse than people realise.
There were fears the veteran Manchester United striker may not play again after suffering meniscus and cruciate ligament damage in April.
At the very least a lay-off of nine to 12 months was anticipated but the 36-year-old former Sweden international defied those gloomy predictions to return to action on Saturday.
“In my recovery I have not rushed anything. People may believe that because I have been out for six and a half months but I have been following protocol and my schedule day by day,” he said. “The only secret has been working hard. Those close to me know what I have been doing – I was working five, six hours a day. When it happened I said to everybody giving up was not an option.
“My only focus was on coming back and coming back better. For that you need to work hard. I know when I’m back it’s my head playing, not my knee. My knee has to follow. But this was not a one-man work, it was everyone’s and it is thanks to them that I am back on the field and can play because if people really knew the real injury they would be in shock that I was even playing.
“But I keep that personal. People think it was only the ACL (anterior cruciate ligament) in my knee, but it was more than the ACL. But it’s sensitive and that’s why I don’t choose to talk about it.”
The uncertainty over Ibrahimovic’s future was exacerbated when his contract with United lapsed during his lay-off. It was not until the new season had begun that a new one-year deal was signed but Ibrahimovic insists there were never doubts.
“It’s fantastic to be playing. Jose said, ‘Do whatever you want, I trust in you and you know what you have to do,’ so I was not worried. The contract is all paperwork and I do the physical work. Even if I had a contract or not I needed to train. I knew I would stay because I wanted to stay. The numbers have never been an issue.
“I could have signed a deal after two months but didn’t because I am honest with myself. I want to stay because I can perform.”
Ibrahimovic, whose stellar career also includes stints at Juventus, both Milan clubs, Barcelona and Paris St Germain, has not looked beyond the end of the campaign.
“I am at the age where I can choose what I want to do. I don’t sign five or 10-year deals. I am just happy to be back playing and doing what I am good at.”