Assigned to the toughest gig in world rugby, Wallabies flanker David Pocock is on a search and destroy mission to stop All Blacks captain Richie McCaw in Saturday's Bledisloe Cup clash in Tokyo.

Hardly rocket science, the Wallabies believe if they nullify McCaw they win the Test at Japan's National Stadium.

Easier said than done, of course, with McCaw having dominated the breakdown in New Zealand's six-match winning streak over Australia dating back to the Wallabies' last trans-Tasman triumph in Sydney last year - when, not coincidentally, the All Blacks skipper was out injured.

Desperate for a solution, Wallabies coach Robbie Deans has taken the radical step of relegating George Smith for the first time in eight Bledisloe encounters since taking the helm last season - and handed Pocock the greatest challenge of his 11-Test career.

Pocock, 21, is under no illusions as to the difficulty of his task at hand, but has a clear understanding of his role.

"The one thing about him (McCaw) is his running lines from set piece to the first breakdown are pretty sharp so that's one thing that you've got to be on top of," Pocock said on Wednesday.

"That will be a massive challenge. He had a bit of a field day in Wellington, where he had a great game (in New Zealand's last-up 33-6 win).

"So trying to minimise just his access to the ball at the breakdown will be a big challenge for us.

"It's more of a team focus of getting rid of him in the rucks."

Pocock credits everywhere man McCaw as the catalyst for New Zealand's constant dominance of the ruck area.

"You don't really notice him revving the boys up too much. He leads more with actions," Pocock said.

"Yeah, the All Blacks are pretty abrasive in the way they play and the way they attack the breakdown so that's definitely got to be one of our focuses this weekend - matching that."

Fellow flanker and newly-appointed captain Rocky Elsom agrees the onus is on the entire team to aim up at the breakdown, where the All Blacks have battered the Wallabies all season.

"The breakdown's a big thing," Elsom said.

"New Zealand rugby probably leads the world at the breakdown and there is a reason for that because it's very important to winning matches."

Deans is demanding his Wallabies maintain focus from start to finish but believes the powerhouse Pocock is better equipped to combat the All Blacks in the fiercely-contested opening exchanges.

"The start to the game is pretty frantic so, as a team, we've really got to pick the tempo up right from the start and maintain that for the full 80 minutes," Pocock said.

"In Wellington, we were in it for a good 60 minutes and then they got away from us.

"It's about getting that consistency for the full game."

Halfback Will Genia, who will be barking orders to his forwards throughout the Test, says there can be no repeat of the Wallabies' ineffective ruck work in Wellington.

"That was obviously really disappointing. We didn't have much opportunity to attack and we had nothing to really build on," Genia said.

"We were stuck defending the whole game and we didn't match them at all in terms of physicality.

"If you don't match them physically, you've got no hope."