Former Ospreys scrum - half Justin Marshall believes Wales will have an advantage over New Zealand in Saturday 's first Test -- .
That the opening encounter of the three - match series is Wales ' one and only chance to make history .
Former Ospreys scrum - half Justin Marshall believes Wales will have an advantage over New Zealand in Saturday 's first Test -- but that the opening encounter of the three - match series is their one and only chance to make history .