Australia are far more threatening at the scrum than their "unjustified" criticism suggests, according to Ireland prop Mike Ross.
The experienced tighthead has been studying the Wallabies' set-piece and thinks Joe Schmidt's men have their work cut out on Saturday.
But the 33-year-old Leinster man anticipates a far tougher battle at the coal face for the second weekend of Ireland's autumn international series.
Ross said: "I think they are very good at retaining their own ball.
"If you look at the statistics most of the times they are sanctioned is on opposition ball, whereas on their own ball they seem to win that fairly handily.
"They have a lot of experience in there - they do get a fair bit of stick but I think a lot of that is unjustified.
"I was watching them against England and I thought they were quite unlucky at times.
"I went through the Italy game too, and they got sanctioned a few times, but at the same time they still put 50 points on Italy.
"It's up to the individual referee of course (how they call the scrum), but most of their sanction is on opposition ball.
"It's probably something for them to look at themselves.
"But I'm not expecting it to be easy by any means.
"They do have good scrummagers, they do have a heavy pack, so it's going to be a tough battle up front again this weekend."
Leinster's 24-year-old McGrath could not understand the fuss, but Ross said his team-mates were unsurprised by his impressive showing.
Ross continued: "I think the scrum went well, it was pretty pleasing.
"We managed to turn over two of theirs, and considering it was the first time myself, Jack and Rory were together as a unit, it went pretty well.
"Jack's a very unassuming man, he was a little embarrassed by all that (winning man of the match).
"But I've seen him come through in the last three to four years and none of this is a surprise to us, because we've seen him develop and seen his big work ethic. He's a big man and he's been playing really well.
"It's good to get a good win over them, especially with them ranked above us.
"In the past year they had done a job on Wales, Scotland and Italy. To be fair to them they lost a few lads through injury so we won't get ahead of ourselves just yet."
Wary of Australia's danger men behind the scrum, Ross said Ireland's tight-five must aim to stop Saturday's visitors at source.
He added: "If you had Israel Folau, Will Genia and Adam Ashley-Cooper in the backs, it would be a shame not to use them.
"If you've got Genia and Cooper operating on front-foot ball it makes things a lot easier for them and far more difficult for us so we've got to go after their set-piece ball.
"You've got to watch Genia like a hawk around the ruck, he can dart and be through and behind you before you know it."