He passed the 300-mark in the first session of the final day of the match as the crowd cheered almost every ball the Kiwi successfully faced when he resumed play on 281 not out.
But it almost didn’t happen as McCullum edged Ishant Sharma when on 293 and the ball fell just short of MS Dhoni.
The 300th run came in the 11th over.
It was a fantastic batting display and saw the Black Caps come away with an unlikely draw having trailed by 246 at the end of the first innings after the tourists racked up 438 on day two.
McCullum faced 559 deliveries in what was the eight longest innings in Test history at 774 minutes 12 hours and 54 minutes and had to battle the back pain which prevented him from keeping wicket.
Shortly before he made his historic triple ton, his overnight partner, debutant Jimmy Neesham, completed his century on a remarkable morning for New Zealand cricket.
McCullum has eclipsed the 299 that Martin Crowe scored against Sri Lanka on the same ground in 1991 and has became the 24th man to score a Test triple hundred.
On day four, McCullum and wicketkeeper BJ Watling (124) scored 352, the highest sixth-wicket stand in Test cricket history.
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