Jonathan Davies of Wales© Picture by: Mike Egerton / EMPICS Sport

Jonathan Davies believes mental toughness must be prominent in Wales' armoury if they are to emerge from the so-called World Cup pool of death.

Arguably the toughest World Cup group in the tournament's 28-year history will begin unfolding next month, with Wales, host nation England and twice-world champions Australia among those battling for two quarter-final places.

"There has to be an element of mental toughness for Wales," former Wales fly-half Davies said.

"They have got to go to Twickenham to play England and Australia, and I think there is hardly anything in it between England and Wales. Australia, we will have to wait and see with their scrum, but their back line is amazing.

"It all depends on [Wales head coach] Warren Gatland's thinking and what he is going to do. They have got a maximum of seven games, and if you win seven games you win the World Cup. Play your best team every game, apart from any niggling injuries, would be my approach.

"If you lose one game, the chances are you are out of the World Cup, and for me, mental toughness is the key aspect for Wales.

"You have got to go in thinking you are going to play every game because I don't think the back-up players are pushing enough, which maybe is the one weakness in the Welsh game.

"Wales have got to play Fiji five days after playing England, but it doesn't matter. They have got to get up and play, and then there are nine days after that before they play Australia."

Wales boss Gatland will name his final 31-man World Cup squad at the Millennium Stadium next Monday.

Three prominent names have already gone through the exit door after British and Irish Lions trio James Hook, Mike Phillips and Richard Hibbard were among a group of players cut from Gatland's training group earlier this month, and Davies says that underlined Gatland's traditionally strong selection stance.

"Everyone knows that he hasn't been scared to wield the axe - he has done it with Wales and the Lions," added Davies.

"He does it because he thinks that is the best decision, and he has been successful. He is very strong in his selection policy.

"We don't know what goes on within the training squad, and the key is what the coaches see day in, day out. It's their call.

"It will be interesting to see how he [Gatland] looks at the Ireland and Italy warm-up games, and then the opening pool fixture against Uruguay leading into facing England.

"Wales tend to start a bit slowly in the autumn Tests and the Six Nations. Sometimes they can catch up, and other times they don't. Wales can beat England. Maybe England start as slight favourites because of home advantage, but that is the only reason."

In terms of the tournament as a whole, Davies has no doubt that reigning world champions New Zealand deserve to be tagged as favourites.

"In the whole history of the World Cup, I can't think of a tournament when they haven't gone in as favourites," he said. "That hasn't changed. They go in as favourites, and it will be a case of who can beat them.

"If you look at the strength in depth of the All Blacks and their decision-making and game-management, I think they are in front of everyone."