Having become the first New Zealander to hit a test triple century early in the year - along with two double centuries which were key to spectacular victories - McCullum yesterday became the first New Zealander to make 1000 test runs in a calendar year, but that was just part of it.
Having got his eye in, he took Sri Lanka's attack apart. Sri Lankan captain Angelo Mathews won the toss. The visitors expected plenty out of a green, seaming pitch, but McCullum ripped the game from them.
He had help, notably from Williamson in a 126-run third wicket stand of which Williamson scored 20; and Neesham, with whom he paired up for a rollicking 153-stand in 117 balls.
But McCullum enjoys centre stage and when he's in an imperious mood and seeing the ball like a pumpkin, watch out.
He has form for picking his moments. Remember his 158 in the first Indian Premier League match back in 2008?
Yesterday, he adorned Hagley Oval and the occasion in similar fashion.
McCullum bristles with aggression. Singles don't interest him.
His stellar year has produced a string of wonderful, contrasting innings, but in a way this might have been the best expression of his work.
At times it looked like it could not last; at others you thought it would never end. He was the playground bully, in the nicest way.
Arriving at the crease in the first over after lunch, McCullum tore into his work. Sixes were slapped with disdain, mostly straight, or to mid wicket, along with one vicious hook which flew hard and flat into the crowd.
There were 11 in all. Nine more and he will have hit more sixes in test cricket than anyone.
Mark that down as a when, not if, long before he's done playing at the top level.
There was the occasional wild smear but that's McCullum. His eye is formidably good, his confidence sky high, and he simply went into one-day mode.
Sri Lanka's bowlers were not good enough, or savvy enough to keep him off strike and work on his batting partners.
Suranga Lakmal was the best of them. McCullum clobbered 26 in an over off him.
Debutant offspinner Tharindu Kaushal went for 159 off just 22 overs. As Bruce Willis put it in Die Hard, welcome to the party, pal.
Sri Lanka didn't help themselves in the opening session, being too wide too often in conditions which certainly offered help. Don't expect New Zealand's bowlers to be as generous when their time comes today.
Sri Lanka weren't helped by their finest player, Kumar Sangakkara, twice spilling catches. Heads went down as the carnage went on.
Neesham will wake this morning hugely satisfied with his innings. He needed it, coming off a lean run and he showed he can strike a ball as cleanly as anyone, including his skipper.
Williamson is up to 898 runs for the year but seemed to lose his way as McCullum charged on, before falling to the best ball of the day.
The onus will now be on New Zealand's bowlers to capitalise.
This pitch will offer assistance to the seamers throughout the match, according to New Zealand batting coach Craig McMillan.
Let's see. But they'll have to go some to top yesterday's events.
McCullum by the numbers
74 balls taken by Brendon McCullum to reach his century. It was the fastest test century by a New Zealander, eclipsing his previous record of 78 deliveries in his last test innings, 202 against Pakistan in Sharjah last month.
11 McCullum's career test hundreds, equal to Nathan Astle and behind only Martin Crowe (17), John Wright and Ross Taylor (12).
4th hundred of the year recorded by McCullum, and when he reached 31, he became the first Kiwi to reach 1000 test runs in a calendar year.
102 out of 131 runs scored by New Zealand in the day's middle session were struck by McCullum.
72.75 McCullum's test average this year with innings of: 224, 1, 8, 302, 7, 17, 4, 3, 31, 25, 18, 39, 43, 45, 202, 195.
33 sixes struck by McCullum in the calendar year, a world record.
11 of those sixes were struck in yesterday's innings, equalling the New Zealand record by Nathan Astle in his double century against England, also in Christchurch, in 2002.
92 sixes in his test career, the most by a New Zealander, and is now eight behind the world record of Australian Adam Gilchrist.
7.84 the run rate during the 153-run stand between McCullum and Jimmy Neesham, which is the third quickest among all 150-plus stands in test cricket.
