On the adjacent wall is the only image displayed in the club's modest temporary boardroom - a black and white mural of the 2014 Asian Champions League-winning side. Only head coach Tony Popovic was portrayed in full colour with his famous post-match comments printed above: ???"We were called a small club yesterday. Today we are the biggest in Asia."

As Popovic sat beneath his own motif announcing his shock resignation as head coach to join Karabukspor on the eve of the new campaign, it wasn't just the hopes of the season that were left in tatters, but potentially the core identity of the club. And he knew it too.

"I told John I have an uneasy feeling in my stomach and a lot of that might be as well from starting the club from scratch," Popovic said.

In 2012, he stood down from his role as assistant coach for Crystal Palace to lead the fledging Wanderers, building it from the ground up. He established a ruthless streak, a resolute mentality and a culture of success born of iron discipline.

Those traits remain in today's squad, but sadly only Mark Bridge - back at the club this season after a year in Thailand - played in that inaugural season. Popovic's strict regime wears out many who go through the club's training base in Blacktown and his reign was marked by a high turnover of players.

The captain's armband did a merry-go-round. Icons were forged then forgotten and a lack of consistency in personnel meant few could make their mark on the club's identity over time. The culture of the team was Popovic's and his only. For the most part, that delivered consistency, results and success but it made the Western Sydney Wanderers a club shaped in his image.

It's not just the first team he influenced but other operations of the club, including its academy. Popovic would return early from away games from as far as Perth just to watch youth teams play. He was a frequent observer at training sessions of teams as young as the under-13s. He would intervene with post-game team talks and analysis when not satisfied youngsters' attitude was befitting of a "Wanderer". To many, he was big brother and he was always watching.

Soon, the club will move into a new training base and headquarters at Blacktown where his fingerprints are all over those designs. You can bet he had his say on the club's requests for facilities at their new stadium being built in Parramatta.

The harsh reality for the Wanderers is that a young coach as successful as Popovic was always going to leave for something bigger. Some expected that would happen as soon as the end of this season when his contract expired. Coincidentally, that would have occurred at the same time Ange Postecoglou will leave the Socceroos. Nobody, not one of his closest confidants, expected any sooner.

He had held firm in the face of a flurry of lucrative offers from China. He turned down an approach to coach Crystal Palace in the English Premier League due to no guarantees of autonomy. As recently as February, he snubbed a chance to coach in the Serie A with Palermo, fearing selection policies wouldn't be solely his to make.

But control of the football department of Turkish Super Lig club Karabukspor ticked all the boxes for his career progression. A handshake agreement with Western Sydney Wanderers chairman Paul Lederer meant his employer wouldn't stand in his way, even it would come at an unheralded cost.

The departure of the man who set the culture of the club could subsequently uproot that of the team. Already goalkeeping coach Zeljko Kalac is set to follow Popovic to Turkey and it's understood assistants Hayden Foxe and Andres Carrasco may also join him on the Black Sea. Nothing yet has been confirmed, but a potential coaching exodus could start as early as Monday morning.

"That may very well be the case," Tsatsimas conceded.

In 2012, a Western Sydney franchise successfully asked the public what its identity should be. Should Popovic's abrupt departure coincide with a staff exodus, what's left of their football department could be staring into the void, asking themselves that same question.