"We live this deployment in Iraq 24-7 so you want to take your mind off things and the Australia-NZ rivalry in rugby definitely rallies the troops.
"The Kiwis keep raving on about their trophy cabinet. Now their dinosaurs like Richie McCaw have cleared out there is more of a chance for the Wallabies.
"Banter like that goes back and forth all the time."
Saturday night's 8pm kick-off in Sydney fits as lunchtime TV fare for the 300 Australians and 100 Kiwis behind the fortified walls of the Taji Military Complex, north of Baghdad.
The base was attacked twice by ISIS suicide bombers at the front gate in June with both bombers and one Iraqi soldier killed.
"It's like walking on the sun here ... hot, dusty and 47 degrees in the shade when you are wearing body armour as well," Sgt Mitchell said.
Sgt Mitchell trains local soldiers to use M16 rifles and machine guns, in tactics, urban clearances, sniper courses and combat first aid.
Winger Drew Mitchell has his 70-Test career in perspective when his father Gordon was in artillery, his late grandfather Rex served in Vietnam and brothers Bronsen and Zane are both in the army.
"We glorify the sporting community but our soldiers are doing far more important work," Drew Mitchell said.
"I definitely believe we don't give them enough kudos. They should be the first ones we honour.
"It is a tough time for the family with Bron away but you try not to think about it too much.
"When he Skypes us he keeps it lighthearted but I'm sure he dilutes the information because he wouldn't want us to worry."
The running joke in the Mitchell family has always been that if rugby never worked out for Drew he would have joined the army but only as an officer as he would not take orders from his brothers.
The Wallabies jersey that Sgt Mitchell has with him in Iraq was one he bought himself because he would not ask for a handout from his brother.
"That would have been a bit rough after Drew shouted Zane and I to the Rugby World Cup last year for the rollercoaster of emotions in the stands through the tight wins and the final loss to the All Blacks," Sgt Mitchell said.
The power of sport works even in Iraq where it is a different shaped ball that has roused the locals in their dealings with Australian Army personnel.
"Like anything, you find your similarities, and as soon as you mention soccer the Iraqi soldiers I teach open up more," Sgt Mitchell said.
"That's especially the case with the Iraq-Australia World Cup qualifier coming up (in Perth on September 1) when we'll organise some kind of celebration with their soldiers and interpreters.
"Sport has meaning for all of us."