Swindon boss hails 'incredible' Luongo
The Robins, who are sitting second on the table and in automatic promotion position, also lose Iraqi Yaser Kasim to next month’s tournament.
While Kasim flew out to join his international teammates, Luongo put in one last Man of the Match performance in Sunday’s 1-0 win over Port Vale.
The 22-year-old earned rave reviews for his shift and is in scintillating form ahead of the Socceroos’ Cup campaign.
"I thought he was incredible," Cooper told BBC Wiltshire after the win.
"We asked Massimo to be the holding midfield player. I'd seen him do it before in the Championship, so I knew he could do it, and I thought he was outstanding.
"I'm sure he leaves us with a heavy heart. He's desperate for the club to do well and he goes with our best wishes.
"He could have ducked out, to make sure he didn't get injured, but he wore his heart on his sleeve and sweated blood for the cause. That's the kind of player we need."