The rain first came on the stroke of tea, both as Australia’s saviour and its tormentor.

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Day three was getting away from the Australians and after a session of gradual unravelling, two young Indian all-rounders were in the process of completely tearing up the home side’s plans.

It was supposed to be a batting day for Australia. Most of the almost 80,000 people who arrived on Saturday did so in the hope of watching Sam Konstas, Steve Smith and Travis Head bat Australia into a winning position.

But there were some annoying errands to take care of before the fun could begin, and Australia’s wicket-taking procrastination soon meant it was bumping up against a looming deadline.

The rain may have briefly halted the progress of Nitish Kumar Reddy and Washington Sundar, and then later ended the day early with the bulk of their work done, but it also cost Australia valuable time in a Test match it can ill afford not to win.

We’re halfway through the fourth Test of this summer, and so by now we have a pretty good grasp of the strengths and weakness of both sides.

In India’s case, Jasprit Bumrah aside, its greatest strength might be the fighting spirit of its youngsters.

While Rohit Sharma battles his demons and Virat Kohli storms around spoiling for a fight, guys like Nitish, Yashasvi Jaiswal and now Sundar have become the chief thorns in Australia’s side.

The straight bat and clear mind of Nitish stood in stark contrast to the acrobatics of Rishabh Pant earlier in the day, who as ever toed the fine line between playing his “natural game” and throwing his wicket away.

If you were kind you would say Pant’s shot — falling onto his back while reverse ramping a ball straight down Nathan Lyon’s throat at third man — was overly ambitious and seriously ill-advised. If you were Sunil Gavaskar on the ABC call, you would call it something else: “stupid, stupid, stupid”.

It seemed at that point as if India was determined to offer this Test up to Australia as a belated Christmas present, after the Kohli-Jaiswal run-out nonsense of the night before. But Nitish’s arrival to the crease changed the tempo of the day.

Nitish batted with purpose and control. He left the ball well and drove it immaculately down the ground, but was equally happy charging and dispatching Nathan Lyon when the mood struck him.

And as the eighth-wicket partnership between he and Sundar grew, Australia became increasingly tired, ragged and devoid of any kind of spark. There were times during the afternoon when this Australian team looked, for lack of a better word, old.

Mitchell Starc had a back problem. Not one that stopped him from bowling, but one that clearly was impeding him and causing him pain.

He spent plenty of time receiving attention from the team physio on the fine leg boundary, and at one point was incredibly slow off the rope in a failed attempt to take a catch. It was a half-chance at best, but it was laboured all the same.

In the same over Lyon chugged after a ball down on the boundary, only to slip over and kick the rope while picking it up. Later in the day Usman Khawaja attempted to slide after a barely moving ball for some reason and nearly detonated his ACL.

Australia did not bowl or field badly by any measure, but in the face of what was spirited and determined Indian resistance was found wanting for real game-breaking inspiration.

Not for the first time, either. Look back at big series in recent years Australia has failed to win — India’s most recent visit four years ago, and the last two away Ashes series most notably — and you will find moments in matches where the game has been right there within grasping distance, but not seized.

Often it has been Australia’s inability to take lower-order wickets that has proven its undoing, and although you absolutely can not call Nitish or Sundar tailenders, it has proven the case again here at the MCG.

There is still plenty of time for a winner and a loser to emerge, but on a pitch that remains a dream to bat on, Australia’s path to victory has narrowed significantly.

The Aussies will now need to bat their way back into a significant lead, upwards of 350 at the very least, while still leaving themselves enough time to bowl India out.

Breaking that down further, that will mean taking the final wicket and smashing about 250 runs in little more than two sessions, leaving the best part of four sessions for a physically sapped bowling attack to take 10 wickets and win the game.

The odds in this game and consequently this series have swung significantly back in India’s favour, and almost all of that can be put down to work of Nitish Kumar Reddy on day three.

His century, laced with late drama as wickets tumbled at the other end, was just the latest in the growing list of turning points throughout this summer-long battle. The challenge is in front of Australia once again, the margin for error smaller than ever.

Between now and day five in Sydney, Australia can not afford any more wasted sessions. Easier said than done against an Indian team with more character than perhaps it has been given credit for.