Son is also a unifying figure who "transcends groups within the squad" according to Postecoglou -- particularly important after several years in which dressing-room fractures were quick to surface during tough spells.
As Spurs prepare for Saturday’s visit of Manchester United -- their first home game under Postecoglou and since losing Harry Kane -- the question around Son is not over his leadership qualities but his form.
Last season was by some distance Son’s poorest in English football since his maiden campaign at Spurs in 2015-16.
He still managed 10 League goals -- a respectable return -- but they were largely confined to a hat-trick from the bench in a 6-3 win over a wide-open Leicester side and five goals in a run of nine games in March and April (which at least suggested he was belatedly finding some rhythm).
For the majority of the campaign, Son was a shadow of the player who shared the Premier League Golden Boot with Mohamed Salah a year previously.
Son has since revealed he spent the season playing through pain due to a hernia injury, which required surgery over the summer, a significant caveat in assessing his form, while he also went under the knife in November to repair a fractured cheekbone.
There is also the fact that practically every member of the squad, Kane aside, underwhelmed as Antonio Conte’s tenure painfully unravelled.
There are no guarantees, however, that Son will automatically return to his best now he is seemingly fit and Conte is gone, and it is down to him to prove that last season was a blip rather than the start of a sustained downturn (he turned 31 in July), all while captaining the side, helping to fill the void left by Kane and adapting to Postecoglou’s game.
Son has thrived in the counter-attacking teams of the previous three Spurs coaches but faces a very different task in the Australian’s possession-oriented team; in last weekend’s 2-2 draw with Brentford, Postecoglou’s front three -- also including Richarlison and Dejan Kulusevski -- struggled to make inroads against the Bees’ five-man block in the second half.
The game against United should be more transitional, which would suit Son particularly if the visitors leave as much space in midfield as they did in their fortuitous opening-day win over Wolves, but he is likely to be spending less time charging into open space and more trying to unpick packed defences now Postecoglou is in charge.
The new head coach has played down the importance of the captain’s armband, calling on all his players to be leaders, but he will hope the extra responsibility can rouse Son from what has felt like a prolonged slumber, and return him to the form which made him one of the finest forwards in Europe.
More than anyone at Spurs, he stands to miss Kane (they shared the most lethal partnership in Premier League history) but a fit and firing Son would immediately go a long way to compensating for the firepower lost with the England captain.