Zlatan Ibrahimovic has likened himself to a lion after his match-winning performance for Manchester United in the EFL Cup final against Southampton.

Ibrahimovic scored twice in the 3-2 victory, with his decisive 87th-minute header the 26th goal of his debut campaign in England. The striker’s age had caused some to question how effective he would be but the Swede, 35, said: “I’m an animal. I feel like a lion. I don’t want to be a lion, I am a lion.”

Asked whether he meant he possessed the hunger of a lion, Ibrahimovic said: “The lion is born a lion – it means I’m a lion. I feel in good shape. I train hard. People who know me from the locker room know that I train very hard. I have an objective every season I go into. And to reach that objective I need to train hard and I need to suffer when I train; that is how I achieve what I achieve.

“I’m from the old school where they work hard and get what they get from doing the hard work, not like the new school where it is easy to get what you want.”

After the final Mourinho said fans should camp outside Ibrahimovic’s house to implore him to sign the one-year contract extension on offer from the club as his terms expire in the summer.

“I have a special relationship with him,” Ibrahimovic said of United’s manager. “When he called [last summer] it was basically: ‘Tell me what number I should wear.’ Let’s see what happens – I mean the moment, how I feel, the situation. We have another two months of the season to go, because according to many I could not do what I’ve been doing.”

Ibrahimovic said his two children had been instrumental in persuading him to join United – “My mind was not here. Then my kids started to bump my head and José called, then I am here” – but that they would not influence his decision on whether to stay. “This time I am the boss, not them.”

He added that there was no other manager he wished to play for or any other country he wanted to experience and that remaining at United did not depend on Champions League qualification.

“I came here and the club wasn’t in the Champions League,” he said. “So it had nothing to do with the Champions League. Somebody made up a story that if they don’t qualify for the Champions League I will not extend. It has nothing to do with that.”

His response when asked whether it would be going downhill if he left United was instructive. “Me or the club?” he said. Told the question related to him, he said: “No, no. I will stop on top. I will not play one game by being Ibrahimovic and for what I did before. If I don’t perform, if I don’t bring results, I will not play.”

Ibrahimovic believes he is improving with age. “I think so. I am still doing what I have been doing every year but some people won’t accept it or admit it because I don’t do it in their home ground,” he said. “I have come to their home ground and now I am doing exactly the same thing I have been doing all the years. I look good. I know I look good. I feel fresh. I feel good. I feel like an animal.

“It is special because I was written off. I was not worried about age because I know what I am able to do. It is because I am here in England. After all these years [people said]: ‘He didn’t come and show himself here.’ But I came.

“And I came when people thought it was impossible for me to do what I am able to do. It feels good. I am enjoying it. The important thing is what I believed. What I predicted. That is exactly what I am doing.”

The EFL Cup winner’s medal is the 32nd of his career. “It will be put in the museum,” said Ibrahimovic. “I have a house only for the medals.”