Trump critic, author, coach: meet Japan's Nils Nielsen

With a pierced ear and sharp suit, there's a touch of rock and roll about the 54-year-old coach with a chaotic backstory who will lead Japan into Wednesday's semi-final against South Korea. 

Nielsen had no professional playing experience after being born with a defect in his back which led doctors to advise him against pursuing a career as a footballer. 

He ignored them up until he sustained an injury while falling over an advertising hoarding in a match and went all in with coaching. 

"I hurt myself and I was lucky the (Danish) federation gave me some special treatment as a coach," Nielsen said.

"I feel very blessed, sometimes when something happens to you (it opens) new doors so you don't have to be sad about it." 

Nielsen, who was born in Greenland, has previously coached Denmark and Switzerland.

He has also used his voice as a native Greenlander to criticise Donald Trump, calling for the US president to be "thrown out of office" over his plans to annex the territory. 

"Greenland is not a fantastic place to grow up and I don't know why they call it Greenland because there's no green stuff," Nielsen said. 

"Yeah there's a bit of moss in the summer down south but other than that it's rocks and ice. It's a strange place." 

Between coaching and a stint as the director of football for Manchester City's women's side, which included Mary Fowler and Alanna Kennedy, the Japan coach found time for extra curricular activities.  

"I wrote a youth novel which has just been translated into English. I'm very proud of that even if I'm not a great writer," Nielsen said.

"I take challenges when I see them and I will also record a song at some point - we just didn't make it yet because we are too busy.

"When I was with the Swiss team there was a girl, a fantastic singer - Rachel Rinast - and we will make a record together, I will talk her into a nice little number." 

Nielsen has had the Japan job for 15 months and has set about turning the 2011 World Cup champions into ruthless winners with a killer instinct. 

He has lamented the politeness and humbleness of Japanese players.

So far at this year's Asian Cup, Nielsen's methods appear to be working - Japan have scored 24 goals and conceded zero going into Wednesday's semi-final against South Korea. 

"They have a different culture and it's only recently Japanese players started playing overseas, they have been very well protected," Nielsen said.

"I learned one thing that if you don't listen and respect what they're saying then you can't learn anything. I don't pretend to know the answer to everything."