The first attempt by Sam Konstas at a ramp shot did not go well. In the windy heat of the MCG on Boxing Day, a swing and a miss was met with a wry grin from Jasprit Bumrah. At the non-striker’s end, Usman Khawaja – 38 a week ago – cracked a smile.

When Konstas failed to connect on a second try minutes later, the writing was on the wall. In a critical moment of a Test series that will define this generation of Australian players, selectors had taken a risk. Konstas had just turned 19, and had played just 11 first class matches. The stakes could not get higher, the spotlight no brighter.

Yes, running in was the best bowler in the world, but those early overs seemed to prove the New South Welshman was out of his depth. The T20 tactics were cute, but this was the Border-Gavaskar, poised at 1-1. Virat Kohli shook his head with a smirk and a beard flecked with grey.

But sometimes old people don’t know what they’re talking about. What followed was one of the most searing chapters in Australian sporting history. All the pressures of the cricketing world were compressed onto the light green square in the middle of this storied ground. Surrounded by more than 90,000 fans, and tens of millions on television, there was no escape. Then: bang, the ensuing explosion a mushroom cloud, re-writing the recipe of red ball cricket.

By the time the opener walked from the field, lbw for 60 from Ravindra Jadeja, he had hit Bumrah out of the attack. The Indian spearhead finished his first spell with a barely believable none for 38 from six overs, conceding at more than a run a ball.

Konstas had sparred with the Indians’ spiritual lead Kohli, a shoulder-to-shoulder that will be looked at by the match referee. The Australian may have backed away against Bumrah to launch him over the slip cordon, but he stood his ground as he stared down Kohli or, in another flashpoint, when Mohammed Siraj gave him words.

More than anything, Konstas had belied expectation. On debut, against Bumrah, in the first session on Boxing Day, it should be not be possible to play the way Konstas did. He charged down the pitch to Siraj short of a length, cut a middle stump-bound yorker for four, and produced more ramps than Arisa Trew’s backyard.

And all that after the best bowler in the world started in imperious form. Once, twice, three times and four, Bumrah beat the outside edge of Australia’s rookie opener. And that was just the first over.

At that stage, the Bharat Army’s flags were waving wildly, their three bays – plus the tens of thousands of Indian fans that filled the ground – enlivening the atmosphere of one of cricket’s great occasions. But as the temperature rose, their enthusiasm was tempered. Australia survived the first five overs scoring barely a run. For the next five, they flowed at more than a run a ball.

Bharat Army organiser, Rakesh Patel, had arrived at midnight in Melbourne, his flights booked long before Konstas’ 19th birthday in October. “Before the first drinks break we should have taken a few wickets, the ball was moving round,” he rued, before Konstas interrupted him with a six as the roaring MCG stood in disbelief. “At his age, on debut, that takes some balls. Fair play to him.”

The six soon became a four, one of several boundary reviews that punctuated the morning. Yet this was a morning where details mattered less than the overall impression. The match still hangs in the balance, the series on a knife-edge. But the blazing, bewildering spectacle of that Sam Konstas innings won’t be forgotten.

He had started the day on the outer, the new kid. At the edge of the loose Australian huddle, he looked around at the grand cauldron, hands swaying nervously. Captain Pat Cummins walked over and put his arm around him.

Konstas may have looked like a boy, but when he took a blow to the groin from Siraj – clocked at 142km/h – there was conclusive proof he was a man. Australians had mostly heard the reports of his feats at state level, caught a grab or two on the news in the lead-up, but this was the first real moment to become acquainted.

To say it was a strong first impression would be an understatement. The daring strokeplay, easy-going nature and agitated top lip – pursed and raised in the corner on the bowler’s approach – offer a glimpse at the person the coming years will fully reveal.

By lunchtime he had earned his place on cricket’s biggest stage. He signed autographs and offered some selfies to a group of young fans . Within seconds the crush was on, an eager flood desperate to get close to Australia’s newest sporting hero.