Chris Rattue: The key reason Richie Mo'unga must start for the All Blacks

Richie Mo'unga and Beauden Barrett show their disappointment at the end of the draw with South Africa. Photosport

Here's the weird irony about Richie Mo'unga's struggles against the Springboks in Wellington.

His poor game actually magnified how important he is, because the spectre of goalkicking deciding the tournament hangs over the 2019 World Cup like smog over Tokyo.

Had the All Blacks cut loose against the mighty 'Boks then Beauden Barrett's substandard goalkicking might have gone relatively un-noticed.

But there can be no doubt now that not only is Mo'unga New Zealand's best goalkicking option, but the art is so important that he has to be on the field for the big World Cup games.

Mo'unga has such an army of support that his failings get overlooked - as the ever-popular Ben Smith's still do – but he had a poor and ineffective game having been given a big match start in Wellington.

Halfback TJ Perenara's delivery probably didn't help and Aaron Smith's passing will open up more possibilities for Mo'unga.

But throw in Ben Smith's concerning and obvious decline compared to Beauden Barrett's lively game at fullback, and it should be debate over for the No. 10 jersey. Mo'unga must play, with Barrett wearing No. 15.

There was a weird moment early in the test where Mo'unga held the ball as the All Blacks decided to take a penalty shot and Barrett wandered in to – seemingly – pull rank.

It's time to hand the ball the other way, permanently.

One theory is that Barrett has a particular weak spot on the field, just to the right of the posts. But at this stage of World Cup campaign, it doesn't really matter what the reasons are, and if there is a remedy.

Mo'unga is striking the ball magnificently, although not as beautifully as Handre Pollard who might be the Ben Hogan of goalkicking.

Goalkicking aside, Barrett was close to spectacular given the brutal state of the game. He can do it all, from cover defence to stepping up as a second playmaker. He can still be a truly great fullback, as opposed to a sometimes muddled No. 10.

The World Cup changes many things.

You have to love the drama and tension the tournament draws out of rugby. World Cup games can put your nerves in a vice grip for 80 minutes. Every little moment counts.

But the World Cup also bashes the life out of the game, which needs to take stock in terms of player safety anyway.

If anyone thinks the hit that RG Snyman put on Brodie Retallick belongs in rugby, or any team sport, then they need their head read. There are too many off-the-ball blindside hits where unsuspecting players are sitting ducks.

The Springboks' rush defence was brilliantly effective because they were allowed to get a head start over the offside line at times.

And the All Blacks have abandoned the beauty they brought to the game a few years ago, because they aren't capable of playing it with the current lineup and the risks could prove fatal in Japan. Damian McKenzie's absence doesn't help on that score either.

But the World Cup is what it is. It's no good pretending otherwise.

South Africa have a truly magnificent and massive pack which chewed the All Blacks up in Wellington. They have a brilliant goalkicker, and an obvious defensive plan even though it is one which could come unstuck against clever ball players.

Once again, the All Blacks suffered through a lack of ball carrying from their starting props, a mobility issue coach Steve Hansen has highlighted this year. Owen Franks and Joe Moody were shown up by the impressive 'Bok loosehead Steven Kitshoff in particular.

I'd have the Springboks as slight World Cup favourites over the All Blacks for now, particularly as the injury-prone Retallick won't be in peak condition even if he does make the tournament.