That's the view of leading Irish rugby journalist Gerry Thornley.
He said in The Irish Times the weekend was like golf's third rounds in tournaments that were known as moving weekends. In this instance it would be four losing teams leaving for home and in some cases it would also signal the end of some playing and coaching careers.
For Ireland the threat was all the more real against the two time defending world champions New Zealand.
"Not only have they never lost a pool match, they have won seven of eight quarterfinals, and excluding third-place playoffs have won 14 of 19 knockout ties.
"By contrast, including a quarter final playoff, Ireland have lost all seven knockout matches," he said.
Speaking with former Crusaders assistant coach and Ireland and British & Irish Lions player Ronan O'Gara, Thornley said Ireland would also face a task in keeping New Zealand's gamebreakers in check.
O'Gara said the players concerned all had great attitudes and were open to new ideas.
"[Wing] Sevu Reece scores tries. That's what he does. [First five-eighths] Richie Mo'unga has deadly acceleration and wicked power. He'd be a massive squatter in the gym. Serious leg strength and power," he said.
[Centre] Jack Goodhue had a good work-rate and a massive engine. He did the simple things well, was very intelligent and very mature for a young player.
Of wing George Bridge, O'Gara said, "I knew straight away he'd be an All Black. Very intelligent, very brave, fast, very durable, massive pain threshold."
Fullback Beauden Barrett was also significant in O'Gara's mind.
"There's few people in the world, in any sport, like Beauden Barrett, who makes a sport enjoyable. There's been very few players who play rugby like him, with his acceleration and his spatial awareness," he said.
Thornley said another factor in the game related to Ireland coach Joe Schmidt.
"There is also the nagging suspicion that Ireland haven't shown their full hand yet, and that they'll have a few new trick plays [courtesy of Schmidt's planning]," he said.
But for O'Gara the requirement for Ireland was more basic.
"Ireland have to get their attack right. They've got to score tries. It sounds simple, but it's going to be fascinating to watch," he said.