Wales face mission improbable against New Zealand on Saturday - and coach Warren Gatland has warned his players they cannot afford any lapses in concentration.
Wales last beat the All Blacks in December 1953, almost 10 years before New Zealander Gatland was born, subsequently losing 23 successive Tests and conceding close to 800 points.
"We've got to concentrate for that full 80 minutes on Saturday. It's not a 60-minute game, it's not a 70-minute game," said Gatland. "You can't afford to have any lapses of concentration for any length of time against them."
Victory for the tourists this weekend would complete another successful Grand Slam tour of Britain and Ireland, while extending Wales' run of games without a win to seven.
Even on their hallowed Millennium Stadium turf, Wales have been made huge underdogs but it is a realistic billing given New Zealand's imperious current form.
Wales, in contrast, are on the back of a 16-16 draw against Fiji. And although Gatland has made nine changes of personnel from that game, recalling key players like Mike Phillips, Stephen Jones, Gethin Jenkins, Alun-Wyn Jones and skipper Matthew Rees, Wales have a Herculean task ahead of them.
"You have got to take the ups with your downs," said Gatland, reflecting on the Fiji result. "The guys have responded really well this week, they've been tight-knit and trained well.
"We saw last weekend with the Ireland-All Blacks game that the All Blacks can have a 10-minute period sometimes when they can score two or three tries."
"A couple of minutes before half-time, and 10 minutes after half-time, the game had gone away from Ireland. We've experienced that on a couple of occasions against the All Blacks as well.
"So that has been our focus, to make sure we fully concentrate for the 80 minutes and don't allow any lapses of concentration or levels of intensity for the All Blacks to get away from you."