Wallabies wary of Biggar's boot
Australia already have discipline problems as outstanding flank Michael Hooper was cited on Monday for an incident in the crushing 33-13 Pool A win over England.
The 23-year-old flung himself into a ruck leading with his shoulder connecting with Mike Brown's head. He was penalised but not sin-binned by French referee Romain Poite.
Such penalties have manna from heaven for Biggar. And Grey said his accuracy with the boot would hurt the Wallabies if they offer him up chances in the Twickenham battle to decide who tops the group.
Biggar, who has magnificently shunted aside the huge pressure placed on him in the absence of injured first choice kicker Leigh Halfpenny, contributed 23 points in the 28-25 win over England which set the rot in in the hosts camp.
"Wales have been very consistent," said Grey, who was a member of the 1999 World Cup winning Wallabies team.
"They play the ball through multi-phases which turns the pressure on your defence.
"If you concede penalties to them then they will crucify you.
"I think also their scrum has been really solid. Warren [Gatland] has the guys humming. They will be fresh and raring to go."
Bernard Foley played a similar role to Biggar for the Wallabies. He was a scoring machine in the 33-13 win over England on Saturday with a 28-point haul that included two tries as well as four penalties and three conversions.
However, the 26-year-old Waratahs playmaker said the Welsh challenge would be vastly different to the more predictable English offence.
"The way Dan Biggar has been able to control the game in terms of his tactical kicking and has been lethal with his goalkicking.
"The Welsh like to have their backs always on the front foot, continually pressing either with the ball in hand or in defence.
"This is going to be a great challenge."
Foley said he had also been impressed by the way the Welsh simply would not give up even when they were 10 points behind England and injured red-shirted players were strewn around the pitch.
"Their ability to continue and stay in the games: the way they fought to get back in that England game, England just couldn’t shake them," said Foley.
"We know they are going to be very passionate and they will be up for the contest for sure."
Foley, whose parents and sister were watching from the stands as he delivered the performance of his life, said there would be no sitting back on their laurels for the Welsh game.
"I don’t think the coaches will let us relax at all," said Foley.
"The way we approached the pool games was we came into it looking to go at it every game and that's still the focus.
"You don't want to lose any game throughout a World Cup. You want to keep that momentum building."
Foley promised a great spectacle for the spectators based on past high scoring tests between the two sides.
"Yeah, we always come up against each other and it always comes down to the last five or ten minutes," said Foley.
"It's just the way the two teams approach the games.
"They tend to be high-scoring with a fair few tries scored. You can’t relax against a quality team like Wales. Their outside backs can really hurt you."
Agence France-Presse
