Indian antagonist Virat Kohli has escaped major sanctions and a ban that would have ruled him out of the series-deciding final Test over a clash with nerveless teen debutant Sam Konstas.

The youngest man to ever open the batting for Australia, Konstas lit up the Melbourne Cricket Ground in an unforgettable Boxing Day blitz.

But his onslaught left Kohli seeing red and the former Indian captain went out of his way to give the teenager a hip-and-shoulder.

Despite outraging many in the cricket community, including Australian great Ricky Ponting and former Indian star Ravi Shastri, Kohli was handed a slap on the wrist, docked 20 per cent of his match fee and handed one demerit point after match referee Andy Pycroft deemed the incident to be a Level One offence.

It was the flashpoint of a day Australia dominated. Play closed with the hosts 6-311 and Marnus Labuschagne and Usman Khawaja both made half-centuries they needed desperately.

Steve Smith, unbeaten on 68 after his breakthrough century in Brisbane and Pat Cummins on eight can set India an imposing first-innings target on Friday.

Pressure is mounting on West Australian all-rounder Mitch Marsh, who was out for four. Travis Head made a rare duck after centuries in back-to-back matches.

Former Australian captain Ricky Ponting was among the experts to put blame on Kohli over the clash, which will be assessed by the umpires and match referee Andy Pycroft.

Ex-Test umpire Simon Taufel told Channel 7 he expected the clash to be classed “inappropriate physical contact” and said officials were “more than likely do something about that”.

Kohli does have priors in this space, but none have been in the last two years, which would have worked in his favour.

India’s batting coach Abhishek Nayar claimed to have not seen or heard of the incident in a post-play press conference.

While Kohli’s escape is a boost to the tourist’s hopes of a series win, Australia’s new kid on the block is a dent.

The fourth-youngest Test debutant has ever battered Jasprit Bumrah — the world’s best fast bowler — out of the attack in a stunning blitz that ended three Tests of torment.

In a major tactical shift at the top of the order, Konstas rode out an unplayable first over by Bumrah before turning the tables on the series’ leading wicket-taker.

He attempted audacious reverse scoops with the 11th and the 14th ball he faced. Then he tried again, with the next one flying over the wicket-keeper and racing to the fence. Then the very next delivery went for six.

Konstas hit six boundaries and two dazzling sixes on his way to 60 off just 65 balls.

He came face-to-face with Mohammed Siraj after striding down the wicket to him, swatted away poorly aimed short balls and worked his crease to access all parts of the ground.

After one over he gestured to rev up the record crowd of 87,242 as if he was the conductor in the middle of the MCG. When he reached his half-century he patted the the coat or arms on his chest with his bat.

It was the highest attendance for any day of cricket against India in Australia.

He inflicted more damage immediately after that, launching Siraj for a four over mid-wicket. His downfall came when India called on Ravindra Jadeja — partnering Washington Sundar in this Test — and he attempted to defend the left-arm spinner.

The onslaught on Bumrah, who has now taken 24 wickets for the series, including 3-75 on Thursday, was a marked change of approach from Australia.

It had been hinted Konstas had been brought in to be more proactive against the new-ball weapon, but Australia couldn’t have dreamed of landing a gut punch like this.

Bumrah didn’t take a wicket until the first ball of his third spell, which was an uncharacteristic half-tracker that Khawaja hit to mid-wicket on 57.

“It was so impactful against Bumrah in the morning session, just knocked India off kilter for the whole morning,” Channel 7 analyst and former Test quick Trent Copeland told The West Australian.

“We just haven’t had that the whole summer, we have some legendary players in the Australian team and it took a 19-year-old with that sort of brave, brash attitude to come out and have a crack at it and it paid off.

“It just makes you think about Plan B and Bumrah has not had to think about anything other than Plan A the whole summer.

“In the first session when the ball is at its newest and the wicket is offering a bit, you have to think about third man, deep square and do you have to bowl away from the stumps? It was just magic.”

The opening day slowed to a canter with Labuschagne and Khawaja at the crease. Smith took it up a level beyond tea after Labuschagne hit a Washington ball to Kohli for 72.

Head and Marsh had the spring-loaded diving board to launch in the final session, but took a late tumble.

Question marks have hung over Marsh all summer as he battles injury niggles that have restricted his bowling after a limited preparation, but the heat will rise before the Sydney Test if he doesn’t make a score, or offer more with the ball, in the coming days.

Marsh’s poor effort to put Bumrah into the Ponsford Stand had him caught-behind pulling, while Head shouldered arms to the same bowler and was bowled for a seven-ball duck.

Alex Carey’s Konstas-inspired attack of the second new ball ended when he copped a back-of-a-length delivery from Akash Deep that seamed away from him for 31 off 41 balls.

India has revealed captain Rohit Sharma is poised to open the batting in the second innings as part of a shift that saw the tourists drop No.3 Shubman GIll. It is likely KL Rahul will take on that role.