The tough Montferrand flanker, who opened the scoring with a try against New Zealand in France's 20-all draw in Paris, reckons the underdog Welsh side have nothing to lose at the Millennium Stadium.
'Wales have a good chance to beat the All Blacks,' Magne said.
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'They have a high-quality pack of forwards and are good at the lineout so they can hope to deny New Zealand some ball and use it to their advantage.
'By analysing the video of our match they will see what solutions we came up with to disrupt the All Blacks.
'One thing is certain - you can't make any mistakes against New Zealand and you must keep your concentration right up to the final second.
'Having time together as a team like Wales have is also a key because it's about gelling together on every detail of the match.'
French manager Jo Maso says Wales must turn into a team of 'trained commandos'.
'Wales must adopt a real commando spirit. It won't be easy but they will have to be competitive like we were. They must be dominant in the ball-winning areas of the game.
'What they must remember is that New Zealand always have an excellent turn of speed - they are very dangerous once they have the ball.'
Maso said Wales had to dominate at scrum-time and in the lineouts.
'You have to completely starve New Zealand of ball in order to do anything, and on top of that you need to really press up on them all the time.
'They are so lively you can't give them any room for manoeuvre. We totally dominated the scrum and the line-out but then were not able to make the most of our possession of the ball.'
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