Dear Zac, What a week you've had.
You had us going when you were called up to ride the pine in Tokyo after poor old Tamati Ellison's calf blew out. But it was not to be.
Then we weren't surprised, but were still thrilled, when you were named to start against Wales in Cardiff. We've been watching, listening and reading ever since.
Just 20 years old, aye. And all that media attention you've handled with aplomb.
You've got something going for you when the great JK takes an interest.
But yesterday was the business, and young man, so were you.
Our first sight of you on the Millennium Stadium - all nervous and tense, then singing the national anthem with pride.
Didn't spot you in the haka, but from then on - well Zac - for a rugby purist like myself, it was the little things.
The fact that the attack coach factored you into the game plan was a huge compliment.
The kick-chase tactics. The chip over the top from Dan Carter which led to the first penalty goal, his grubber which allowed you to make a crucial tackle that almost led to a try to Brendon Leonard in the first half, and ultimately the second penalty goal.
Your work under the high ball on defence and attack was superb - a big step up - and it was great to see that security. It allowed the All Blacks to regroup easily, and to launch attack.
I particularly loved the way you took a high ball late in the match, then went on the double around to open up play as I haven't always been a fan of your counter-attacking choices in traffic.
There were a number of nice linking touches - quick hands, timely insertions, one of which almost led to Conrad Smith scoring, others which could have turned into something with better execution around you.
Intelligent, unselfish play.
And you grew in the second half.
There you were arriving at rucks - workrate off the ball, understanding the team pattern is so important at this level.
You handled the pace of the game easily - not that speed has ever been a problem.
And I loved your inventiveness and determination to attack even in such a tight game - the quick throw-in early on, a dab down the left, the chop back infield and drive for the line which made Andrew Hore's try.
And that was the only time we crossed the white line, so that should feature in the next edition of Men In Black.
Your defining moment certainly will! What a great chase to run down the Welsh lock and knock his pass away so late in the match. Nobody - not even Graham Henry - can teach that.
It would have been so easy for you to sit back and see what played out.
Nobody would have blamed you, after all it was Jimmy Cowan who threw the intercept pass.
But in that instant you showed so much - we call it digging deep, desire, hunger, heart, playing for your mates.
But it requires a true competitor's brain to instruct the body that it can and it will. You told TJ post-match you were "buggered", that fear of losing on debut drove you on.
That would have been like beautiful music to each and every All Black fan's ears.
You also criticised your mistakes - and quite right, there was a loose pass, and a missed tackle.
But look around you - even Dan "The Man" makes mistakes.
This was a true Test match, you were examined and you finished well and truly on the positive side of the ledger.
Zac - and I'm sorry, you're going to have to live with this - that was a sensational debut.
Take it as it comes over the coming weeks, because Sitiveni Sivivatu and Cory Jane will make it tough for you.
Keep your head screwed on, work hard, improve your game further, soak up the knowledge.
But for today you can reflect on the fact that in the white heat of international rugby you proved you were worthy of everything the words "All Black" stand for. You are on your way.
Your mother and your brother will have told you of their pride.
And without any shadow of a doubt you have honoured the memory of Rob Guildford, your late father.
Well done, young man.