With 10 members of the European Cup champions selected in the Irish touring party, Williams is better qualified than most when it comes to evaluating the Wallabies' first opponents of Deans' tenure.
And the former Wallaby backrower is expecting big things from the men in green.
"They're very hardened and (established) combinations are a big thing for them," Williams said of the Irish side.
"That's a quality side that they're bringing out, I suppose maybe in the past the quality hasn't been there.
"But with the likes of Paul O'Connell, Denis Leamy and Jerry Flannery in the forward pack along with John Hayes and Marcus Horan, like I said, they're all quality players coming off a great (club) season."
Williams said the Irishmen's strength is not reserved to their formidable pack.
"(Brian) O' Driscoll's going to be there, Ronan O'Gara's at the top of his game, and (Eoin) Reddan and guys like Shane Horgan so that's a world-class team that they've got there."
Asked what expectations the Irish side would carry into the clash Williams said: "It's a favourite thing of theirs to come in through as the underdogs.
"But I think realistically when you look at the quality of player that they've got ... they're some of the best players in the world.
"They'll probably publicly be playing down their expectations but certainly they'll be looking for a good performance this week coming against New Zealand to try and keep that momentum going.
"Obviously like I said with Munster doing well in the Heineken Cup, they've got a forward pack there that's got good momentum coming in to the national team and they'll want to carry that over into their Test (team)."
The Wallabies completed their first training session of the Deans era in Sydney on Tuesday as preparations for the gruelling season ahead intensify.