Rugby World Cup Final 2015: Key Battles for New Zealand vs. Australia

One of the biggest matches in Rugby World Cup history is almost upon us as New Zealand and Australia prepare to contest Saturday's final in a fixture packed to the rafters with star talent.

Both teams have managed to make it to Twickenham with minimal injuries or absences, maximising the fans' chances of seeing the best possible XVs head-to-head at the climax of the competition.

Two in-form packs and a lengthy list of world-class backs make for a healthy selection of key battles to watch out for in Saturday's finale, the most important of which are discussed in further detail here.

1. Julian Savea vs. Adam Ashley-Cooper

Julian Savea is runaway favourite to finish this year's World Cup as top try-scorer, coming into Saturday's duel with eight to his name already—despite being somewhat muted against the Springboks last weekend.

But while the Hurricanes wing simply didn't get his chance against a stern South Africa defence, upcoming opponent Adam Ashley-Cooper ran rampant with a hat-trick against the far more exposed Argentina.

It was a feat Savea himself matched against France in the quarter-finals, and the fact two of those three scores have been nominated for international try of the year shows just how potent an attacking force he is.

The key difference between Savea and Ashley-Cooper is that, while "The Bus" is more than happy to drive his way through opponents, the Wallabies star's triple against the Pumas all came in massive amounts of space.

One would be inclined to believe the All Blacks won't be as generous allowing overlaps come Saturday, meaning Ashley-Cooper's tactics will need a dramatic shift if he's to beat New Zealand's best.

2. Brodie Retallick vs. Kane Douglas

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What a return to international rugby it's been for Kane Douglas, who left Leinster for the Queensland Reds in July to end a Wallabies exile stretching back almost two years. He'll now lace up for a World Cup final against New Zealand.

The lock's impact has been telling, too, as he's done well to keep Dean Mumm on the bench and made a huge 15 tackles in the semi-final against Argentina last Sunday—second only to Scott Fardy.

Douglas, 26, is part of that new breed of lock who tends to function almost as another back-rower—energetic and athletic in their practice—but New Zealand's Brodie Retallick also belongs among that bunch.

Many are tipping this to be the best World Cup final ever, delivering a fast and fluid contest, but two tremendous packs could easily make it quite the opposite, with only one of the 24 lineouts played between these two teams in the semis lost to the opposition.

Retallick, 24, is a terrifically mobile asset given his size, but Douglas will need to match his opposite number step for step in order to quell his substantial influence.

3. Dan Carter vs. Bernard Foley

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Dan Carter emerged victorious over Handre Pollard in the semi-final in what turned out to be a fierce kicking fixture between New Zealand and South Africa, but Bernard Foley provides no cause for respite.

The Waratahs man was at his chipping and shimmying best against a disorganised Pumas team for patches of his semi-final win, and he is finally forming a partnership with Will Genia to threaten the world's elite.

Again, the Wallabies fly-half is in for a far different examination this time around as it's unlikely he'll be launching the same kind of ridiculous mis-passes that delighted Twickenham against the Pumas.

Ex-Australia centre Tim Horan was in awe of Foley's performance, but Carter can also pull off those plays to unlock the All Blacks' back-line weapons—best shown in the offloading masterclass against Les Bleus.

In the end, though, this is a final, and the two fly-halves will most likely be critiqued for their kicking as much as anything else—the only question is: Who can we expect to cope better should a drop goal come about?

4. Richie McCaw vs. Michael Hooper

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Saturday's openside head-to-head will almost act as the passing of a torch in international rugby as Richie McCaw, arguably the best No. 7 ever, takes on Michael Hooper, one who would attempt to steal his throne.

The Wallabies back-rower turns 24 two days before the final, and what a birthday present it would be if he were able to best a legend of the sport in an area of this match that will be focused upon with burning interest.

David Pocock, Kieran Read, Scott Fardy and Jerome Kaino will complete the setup to make for a stupendous back-row battle, but Australia icon John Eales believes the current Wallabies crop have what it takes to win, per Darren Walton of Stuff.co.nz:

"

We are the best in the world at the breakdown, pilfering the ball but also the pressure the guys are putting on. The line speed is really good.

Michael Cheika has done a wonderful job developing this team. I think they showed that in Sydney (when the Wallabies beat the All Blacks 27-19). 

When we've got this team with this combination on, I think we are and we've proven that in a number of games.

"

McCaw, 34, will be considered slightly fortunate by some to be playing this Saturday after escaping citation for a clash with South Africa's Francois Louw, and what a boost his experience and engine will be for coach Steve Hansen.

Hooper hasn't had as many highlight moments as he might have hoped for in this tournament so far, and he must ensure the occasion doesn't allow his temper to flare if he's to give his team their best chance of victory.

5. Ben Smith vs. Israel Folau

Another clash between these two teams almost means another mouth-watering fray between Ben Smith and Israel Folau, undoubtedly the two players competing for the title of world's best full-back at present.

We tend to describe Smith as the more conservative of the pair, a versatile athlete who can function just about wherever he's asked, while Folau is supposedly the renegade, that marvel capable of functioning outside the box.

Except we haven't seen much of that Folau at the Rugby World Cup 2015, while Smith's swashbuckling display against the Springboks last weekend earned him man-of-the-match honours.

Folau's momentum has been interrupted by injury at the tournament, and while his average of 68 carrying metres per match is impressive, it's still not of the standards we've come to expect of him at his best.

It could be as simple as this for Australia on Saturday—get Folau firing and there's every chance of an upset, but if his quiet patch continues, he's at risk of being outshone by Smith, especially if Carter opts to use high ball once more. 

All statistics come courtesy of ESPN Scrum.