Standing in as the 'interim coach' of the Matildas for almost an entire calendar year, Sermanni expected to be finished by Christmas of last year.
Football Australia undertook a gruelling ten-month 'worldwide' search for a permanent successor to Tony Gustavsson, who was not offered a new contract following the Matildas' underwhelming 2024 Summer Olympics campaign.
That search ended last week with Melbourne-born supercoach Joe Montemurro putting pen to paper on a three-year contract that will see the Tillies through to the 2028 Olympics in Los Angeles.
With what could well be his final match as a professional football manager, Sermanni's career went full circle in the national capital of Canberra, a city that the Scotsman holds dear.
Sermanni spent the final five years of his playing career in Canberra, first with Canberra City in the then-top flight National Soccer League before dropping down into the semi-professional Canberra Croatia, who played in the ACT's regional first division.
He would then begin a 36-year coaching career in Canberra, first as a player-manager with Canberra Croatia and then working at the Australia Institute of Sport (AIS), honing his talent identification and youth development skills with young footballers, both male and female.
It's an aspect of women's football in Australia that Sermanni believes needs more work to get the Matildas back to their best.
"We need to put resources into development like the NTC programs," Sermanni told reporters after the Matildas' 4-1 win over Argentina in Canberra.
"About ten years ago they collapsed. You don't notice your development collapsing overnight - it takes time and then all of a sudden we turn around and notice we've got all these great players but they're all 30+ (years old).
"We need to put more resources, time and effort into talent identification and the development of young players from age 15 onwards."
Sermanni oversaw 151 games with the Matildas across three stints, first in the mid-1990s and then between 2005-12 before returning as interim in 2024.
30 years on from when the Australian women's team would play at the AIS grounds in front of family and friends, the Matildas have become one of the most popular sporting outfits in the country - a feat Sermanni described as "a dream come true".
Monday night's friendly against Argentina set an all-time record (25,125) for the largest sporting attendance for any event in Canberra, men's or women's.
"It's bizarre. I've never witnessed a crowd quite like a Matildas crowd, even when I played in England. There has never been an atmosphere as unique as this.
"The crowds are just phenomenal. I pinched myself every time I walked out to a Matildas home game. The passion of the crowd, the size and the noise make an amazing atmosphere.
"Back in the days when there were essentially only family and friends coming to games, we dreamt of stuff like this ... Every time we play here in Australia, I stand and look at the crowds, and I'm just astonished.
"The fact that we can come out on a cold Monday night (in Canberra) and fill out a stadium is fantastic."
When asked to define the legacy of his third stint in charge, Sermanni believes he has made the most of a difficult situation.
"I felt the last Olympic campaign hurt the team greatly. There were a lot of expectations internally and externally and things didn't go to plan.
"I felt that when I came into the squad I felt the confidence both collectively and individually was at a fairly low ebb. In that time we've been able to bring back a bit more confidence and also bring players who have been outside of the squad in and feeling they're a part of it. If anything, I feel I have achieved that.
"When we've got a fully fit and healthy squad, I think the Matildas is still a very competitive team. People forget we were so close to getting silver at the last World Cup and the (2020) Olympics.
"The experienced players are still very influential and fit. We've got some good young players coming through and the squad is in not as bad a shape as some people perceive it is."
So what's next for the 70-year-old football tragic after 52 almost continuous years of playing and coaching?
Sermanni says he has "had chats" with Football Australia about his next stage, but that nothing has eventuated in terms of offers or proposals.
"I'm an unemployed pensioner now," Sermanni joked.
"I'll just see what comes along. If nothing comes along, I'll put my feet up and relax."
What's for certain is that he has nothing left to prove.