Sam Konstas’ first attempt at a ramp shot didn’t go well. In the windy heat of the MCG on Boxing Day, one hit and one miss from Jasprit Bumrah was met with a wry grin. On the non-striker side, Usman Khawaja – 38 years old a week ago – smiled.

When Konstas failed to connect on his second attempt a few minutes later, the wall was up. At a critical moment in a Test series that will define this generation of Australian players, the selectors had taken a risk. Konstas had just turned 19 and had played just 11 first-class games. The stakes couldn’t be higher, the spotlight couldn’t be brighter.

Yes, the running-in was the best bowler in the world, but these early overs seemed to prove that the New South Welshman was out of his depth. The T20 tactics were nice, but that was the Border-Gavaskar, who was 1-1. Virat Kohli shook his head with a grin and had a gray-flecked beard.

But sometimes old people don’t know what they’re talking about. What followed was one of the most painful chapters in Australian sporting history. All the pressures of the cricket world were compressed onto the bright green pitch at the center of this historic ground. Surrounded by more than 90,000 fans and tens of millions watching on television, there was no escape. Then: bang, the ensuing explosion, a mushroom cloud that rewrites the recipe for red-ball cricket.

By the time the opener left the field, lbw for 60 by Ravindra Jadeja, he had knocked Bumrah out of the attack. The Indian spearhead ended his first innings with a hard-to-believe zero for 38 from six overs, conceding more than a run per ball.

Konstas had battled with the Indians’ spiritual leader Kohli, a shoulder-to-shoulder duel that will be watched by the referee. The Australian may have backed away from Bumrah to throw him over the barrier, but he stood his ground as he stared at Kohli or, in another flashpoint, as Mohammed Siraj gave him the words.

Above all, Konstas had refuted expectations. On debut, against Bumrah, in the first session on Boxing Day, it shouldn’t be possible to play the way Konstas did. He stormed down the pitch to Siraj, who was just short of a length, slashed a mid-stump-bound yorker for four and produced more ramps than Arisa Trew’s back court.

And all this after the best bowler in the world started in confident form. Once, twice, three times and four times, Bumrah hit the outside edge of the Australian rookie opener. And that was just the first time.

At this point, the flags of the Bharat Army were flying wildly, their three flags – plus the tens of thousands of Indian fans filling the ground – enlivening the atmosphere of one of cricket’s biggest events. But as temperatures rose, their enthusiasm waned. Australia survived the first five overs and barely scored a run. In the next five games they ran at more than one run per ball.

Bharat Army organizer Rakesh Patel had arrived in Melbourne at midnight, his flights booked well before Konstas’ 19th birthday in October. “We should have taken a few wickets before the first drinks break, the ball was moving around,” he lamented, before Konstas interrupted him with a six as the roaring MCG stood in disbelief. “At his age, making his debut, it takes a lot of courage. Fair play to him.”

The six soon became a four, one of several boundary checks that marked the morning. But that morning, details mattered less than the overall impression. The game is still on the line, the series is on a knife edge. But the fiery, bewildering spectacle of that Sam Konstas innings will not be forgotten.

He had started the day with the outside, the new child. At the edge of the loose Australian group, he looked around at the cauldron and moved his hands nervously. Captain Pat Cummins came over and put his arm around him.

Konstas may have looked like a boy, but when he took a punch to the groin from Siraj – at a speed of 90mph – there was conclusive evidence he was a man. Australians had largely heard the reports of his performances at national level and caught one or two stories on the news beforehand, but this was the first real moment of getting to know each other.

To say it was a strong first impression would be an understatement. The daring stroke play, the easy-going manner and the excited upper lip – pursed and raised in the corner as the bowler approaches – offer a glimpse of the persona that the coming years will fully reveal.

By lunchtime he had earned his place on cricket’s biggest stage. He signed autographs and offered a few selfies to a group of young fans. Within seconds the crowds were thick, an eager flood desperately trying to get close to Australia’s newest sporting hero.