One can only imagine what was happening within — and around the group — during that time but Duncan says the team have rebounded well.
"That's done and dusted," said Duncan. "We try not to talk too much about that. We can learn from it but we are focussing on our upcoming games and want to improve and do better."
"We don't dwell on it. Obviously you can't ignore what happened but the team is in a completely different head space and the environment is such a positive one because of what happened.
"I feel the team is stronger in a way and more connected. Looking back now that was just a little blip in the scheme of things and we are focussing on what we can do now to go forward."
119-game-veteran Duncan, who retired in 2017 before returning to the fold earlier this year, was an outspoken critic of Heraf, and called for his resignation in the wake of the Japan match.
"It was a real deep sadness seeing the girls so restricted in their home game," said Duncan. "You wait all your life to play in a home game [like that] and everyone [was] limited to a shell of a player that they really were.
"I was so wound up about it - in utter disbelief. In my opinion I just had to be the voice and I shared my voice and my disbelief. At the end of the day, [it] helped with the momentum to get a proper investigation done."
Duncan hung up her boots at the conclusion of the Cyprus Cup in May 2017, after a career that encompassed three World Cups, three Olympics and club football in five countries. A qualified teacher, she spent last year in a "full on" job as head of P.E. at Stonefields school.
But a sense of unfinished business — and the appointment of Tom Sermanni as coach — has brought her back.
"It was good to have a go at what they call real life and working," laughed Duncan.
"But I wanted to take the opportunity to work with a highly respected new coach.
"And I felt I had more to give back to the team and the girls and thought I don't want any regrets later down the road. I thought I would give it a go and see how I goes."
Duncan is full of praise for Sermanni's work so far, saying the 65-year-old Scot is "just what the team needs.
"He has a lot of experience," said Duncan. "It's refreshing to have someone when you don't feel like you are playing from fear or you are playing restricted and he is not over complicating things."
The Ferns have an unprecedented build-up to the Women's World Cup in June, with six more games against quality opposition.
Duncan has a battle to make the side — there is no shortage of quality in the midfield area — but she is going to enjoy the ride.
Katie Duncan
Age: 31
Football Ferns debut: 14 November, 2006 vs China
A-Internationals: 119
Overseas clubs: SC 07 Bad Neuenahr, Notts County, FC Zurich and Melbourne Victory
Katie Duncan
