Defending champion New Zealand and archrival South Africa meet in the opening game to ensure a fascinating start to Rugby World Cup Pool B.

The All Blacks (2011 and '15) and Springboks (2007) have won the last three World Cups and five of the eight played, and are obvious choices to progress to the quarterfinals. The big question is, in which order?

Not long ago the All Blacks would have been clear favorites but an underwhelming Rugby Championship saw them lose their No. 1 ranking and, more crucially, some of their aura.

The Springboks, after a slump from 2016-2018, have been growing in confidence since Rassie Erasmus took over as coach and won the southern hemisphere title for the first time in 10 years this season.

The last four games between the All Blacks and Springboks have been decided by two points or less — the most recent was a 16-16 draw. Whoever wins in Yokohama on the second day of the World Cup will take huge momentum.

Italy, Namibia and Canada are the other teams in the group and they all face an uphill task to qualify ahead of the big two.

Here's a closer look at Pool B:

NEW ZEALAND

Coach: Steve Hansen

Captain: Kieran Read

Best RWC Performance: Champion: 1987, 2011 and '15.

Last 5 RWCs: 2015-W, '11-W, '07-QF, '03-3rd, 1999-4th.

Outlook: Although New Zealand underperformed in the Rugby Championship, its last two results before the World Cup were compelling: 36-0 over Australia and 92-7 over Tonga. The squad has world-class depth in every position and maybe finishing third in the Rugby Championship was the wake-up call needed to focus minds on the World Cup defense. The All Blacks are still the favorites in Japan.

Players to watch: Richie Mo'unga appears to be Hansen's choice for the No. 10 jersey ahead of Beauden Barrett but both playmakers are key to the All Blacks' chances of winning three titles in a row — no team had successfully defended the World Cup before New Zealand did it four years ago. Hansen thinks the duel playmaker tactic, with Mo'unga at flyhalf and Barrett switched to fullback, will get the best out of both of them: Mo'unga's tactical kicking and link play and Barrett's eye for a gap and blistering speed. Brodie Retallick is arguably the best lock in the world and the All Blacks will be desperate for him to recover fully from a shoulder injury.

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SOUTH AFRICA

Coach: Rassie Erasmus

Captain: Siya Kolisi

Best RWC Performance: Champion: 1995 and 2007.

Last 5 RWCs: 2015-3rd, '11-QF, '07-W, '03-QF; 1999-3rd.

Outlook: Erasmus holds the secret for South Africa and has turned the Boks around in the space of a year. South Africa plummeted to new depths under former coach Allister Coetzee, including a 57-0 humiliation by the All Blacks in 2017. Erasmus took the team to victory in New Zealand a year later. Erasmus has the advantage of also being the South African rugby union's director of rugby, giving him the latitude to make unconventional decisions. In the Rugby Championship, he split the players into two squads and left one at home to play Australia while a group of frontline players were given a week off to rest and acclimatize in New Zealand before the next game. It worked, with South Africa going on to win the tournament and also resting senior players ahead of the World Cup.

Players to watch: Lock-turned-flanker Pieter-Steph du Toit seems to have no weakness. He carries the ball strongly and makes mountains of tackles each game. His stamina is surprising for a man who is 6-foot-6 and 120 kilograms. Handre Pollard calls the shots for the Springboks from flyhalf. Scrumhalf Herschel Jantjies will likely start on the bench but has a knack for scoring tries; two on his debut against Australia in July and a match-saving last-minute try in his second test against New Zealand.

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ITALY

Coach: Conor O'Shea

Captain: Sergio Parisse

Best RWC Performance: 2007: won two pool matches (vs. Portugal, Romania) and narrowly lost 18-16 to Scotland to miss out on the quarterfinals.

Last 5 RWCs: 2015-Group, '11-Group, '07-Group, '03-Group, 1999-Group.

Outlook: Italy has placed last in the last four Six Nations tournaments without winning a game and has just one win in nine tests this year — against Russia. The Azzurri should see off Namibia and Canada but beating New Zealand and South Africa appears out of reach, as do the quarterfinals once again.

Players to watch: Captain Sergio Parisse is the third most capped player of all time behind Richie McCaw and Brian O'Driscoll but it'll take more than just the No. 8's 140 tests of experience to get Italy to the quarterfinals for the first time. Parisse will need help up front from fellow loose forward Braam Steyn, who was born in South Africa, and lock Dean Budd, born in New Zealand. Both are set to play against their countries of birth. Utility back Edoardo Padovani scored tries in each of Italy's first three games in this year's Six Nations.

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NAMIBIA

Coach: Phil Davies

Captain: Johan Deysel

Best RWC Performance: 2015: Came within a point (16-17) of beating Georgia and registering first RWC win.

Last 5 RWCs: 2015-Group, '11-Group, '07-Group, '03-Group, 1999-Group.

Outlook: Former Wales international Davies first took charge of Namibia in the months before the last World Cup and there was marked improvement, with Namibia putting in a brave performance against Tonga and just missing out on an historic win over Georgia. The Namibians will likely be targeting the Canada game as their best chance of claiming the victory that has eluded them at the Rugby World Cup.

Players to watch: Harlequins loose forward Renaldo Bothma was meant to captain Namibia at the World Cup but retired from internationals days before the squad was announced, leaving center Deysel to take over. Hooker Torsten van Jaarsveld, a barreling frontrower who loves to run with ball in hand, has played Super Rugby in South Africa. Scrumhalf Eugene Jantjies will be playing in his fourth World Cup.

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CANADA

Coach: Kingsley Jones

Captain: Tyler Ardron

Best RWC Performance: Quarterfinals: 1991.

Last 5 RWCs: 2015-Group, '11-Group, '07-Group, '03-Group, 1999-Group.

Outlook: Canada was the last team to qualify for the World Cup, coming through in the repechage playoffs ahead of Germany, Hong Kong and Kenya. The mere fact Canada had to go through that indicates the team's slide since it beat Fiji and Romania and pushed France close to make the quarterfinals in 1991. That year, the Canadians were even competitive in a 24-13 loss to defending champion New Zealand in the quarters. The meeting with the All Blacks in Japan is unlikely to be as close and coach Jones' Canada will probably be fighting with fellow Welshman Davies' Namibia to avoid last in the group.

Players to watch: Loose forward Ardron is clearly Canada's best player, good enough to be signed by New Zealand Super Rugby team the Chiefs last year. Canada's other source of inspiration is veteran winger DTH van der Merwe, the country's record try-scorer.

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