'Tired' Son sparked Spurs says Postecoglou
Postecoglou's side were rocked by Tahith Chong's third-minute opener for struggling Luton in north London.
But Tottenham captain Son led by example as he ignored the fatigue from a draining return trip to Asia for South Korea's World Cup qualifiers against Thailand.
He hit both posts during the first half before Brennan Johnson created the leveller when his dangerous cross was booted into his own net by Luton defender Issa Kabore.
Johnson turned provider again in the 86th minute from Timo Werner's cross when he teed up Son, who slotted home via a deflection off Daiki Hashioka to earn the hosts a vital three points.
"I am sure he feels tired. Yeah, absolutely. It's tough. When I was national team coach of Australia, we had quite a few players playing this side of the world," Postecoglou said.
"They're long trips, there is time difference but like I said before he never looks for those clutches, Sonny.
"For him when he is available, he wants to play to the highest possible level and he keeps doing it."
Son's 15th goal this season moved him above 1961 double-winner Cliff Jones into fifth place in Tottenham's all-time scoring list on 160 goals.
But more significantly for Postecoglou, it kept Tottenham firmly in the hunt to qualify for next season's Champions League via a top-four finish.
Praising Son's dedication to club and country, the Tottenham boss said: "Playing for his national team is hugely important to him.
"Playing for this football club is hugely important to him and he wouldn't compromise either by letting his standards drop.
"Irrespective of opposition or whatever game it is, he has this really high level of expectation on himself to be the best he can be all the time. It's very hard to be like that.
"But he wants to maintain the highest possible standards whenever he plays and you see that with his football, his efforts, his leadership now so it's all encompassing.
"Look, he's been a brilliant footballer for this club for a long time and hopefully for many years to come."