IF New Zealand’s players need a reminder of how quickly a Rugby World Cup campaign can come to an end, they need only watch England going through the motions against Uruguay tomorrow. Touted as potential winners one minute, Stuart Lancaster’s side will leave with their tails between their legs once they have completed the deadest of dead rubbers at Manchester’s Etihad Stadium.

Whatever happens when they face Tonga at St James’ Park tonight, the All Blacks know they will not be suffering a similar fate. With three wins from three so far, the reigning champions are guaranteed to top Pool C and head on to a quarter-final in Cardiff’s Millennium Stadium next Saturday.

From that point on, however, any room for error will disappear. Knock-out rugby begins, and each time the referee blows his final whistle, one of world rugby’s big boys will be on their way home.

“We are approaching the quarter-finals, and that is when teams begin to topple,” said centre Conrad Smith, who was a member of the triumphant All Blacks squad that lifted the World Cup trophy in 2011. “It is always going to happen to someone, and that just heightens the anxiety and intensity. Everyone has felt that happen.

“It was going to be a shock whoever went out (from England’s pool) because it had to be one of the top teams. The thing that added to it is the fact that England are hosts, and it dawns on you how cut-throat this tournament is.

“That is just the reality of it, and it will keep happening for the next few weeks. England are the first good team to go out – but they won’t be the last.”

New Zealand will discover the identity of their quarter-final opponents on Sunday, with the losers of the game between France and Ireland in Cardiff due to face them in the Welsh capital a week tomorrow.

Whoever lines up against them in the Millennium Stadium, the task is likely to be considerably tougher than anything they have faced in the tournament so far.

The All Blacks were briefly extended as they saw off Argentina in their opening game, but their last two wins over Namibia and Georgia have been achieved at a canter, and tonight’s encounter with Tonga is unlikely to be much more testing.

The reigning champions will almost certainly head into the last eight with a 100 per cent record, but their performances to date have not hit the heights that might have been anticipated prior to the start of the tournament.

Putting 58 points on Namibia and 43 points on Georgia has led to a degree of unhappiness back in New Zealand, and while the All Blacks players dispute suggestions that they have underperformed in their last two outings, there is a shared acceptance that things must improve tonight.

“We’re fairly happy with the way we’ve been trucking, but we realise we need to keep improving,” said fly-half Dan Carter. “We’ve got another opportunity this week against Tonga, who are going to be tough competition, and it’s important that we step up and improve.

“We’ve had a really good week so far in terms of preparation. We’ve been trying a few new things, and I guess the most important thing is that we’ve worked hard early in the week.

“At times we’ve probably been over-thinking, but we’re at our best when we just play. We’ve worked hard early this week, trying to get a clarity of detail, so now the back end of the week is just about going out there and doing it.”

Carter and Smith are two of the more senior members of the squad, and the pair were quick to pay tribute to Ma’a Nonu, who will become only the sixth All Black in history to win a century of caps when he runs out on Tyneside tonight.

Nonu’s international career has been something of a rollercoaster, with early concerns over his defensive capabilities and positional play initially resulting in him being shuffled off to the sevens squad rather than featuring in the 15-man code.

A brief flirtation with rugby league ended when he was restored to the senior All Blacks set-up in 2008, and the last seven years have seen him emerge as one of the world’s leading centres.

“I’ve been fortunate to have played a lot of rugby alongside him, and to see his growth has been amazing,” said Carter. “Earlier on, when he was in and out of the All Blacks, that will have been tough.

“But he is a big part of this side and, since 2008, he has really established himself. He has grown as a player and really matured. He is a leader, and his professionalism off the field has impressed me.

“It’s awesome having him next to me. He is a big man, he has grown as a vocal player, and now he gives me a lot of direction.

“He is my eyes and ears because he relays what he sees, and helps me with my option taking. That makes a huge difference, and when you need to take the ball over the gain line, he’s a great option.”