'What is going on': Disbelief over crazy Boxing Day moment

Cricket fans have hit out at the Decision Review System (DRS) after an eventful opening day of the Boxing Day Test that ended with India on top against Australia.

Aussie quick Mitchell Starc landed a late blow on India after the hosts were rolled for 195 on Saturday.

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India went to stumps at 1-36 as the tourists endured 50 minutes of supreme fast bowling on the most lively MCG pitch for years.

Starc trapped Mayank Agarwal lbw for a duck to end the first over, evoking memories of India's record collapse in Adelaide last week.

Pat Cummins should have had opener Shubman Gill out in slips in the fifth over, but Marnus Labuschagne put down a fast-moving chance.

Debutant Gill (28 not out) made the most of the let-off, showing poise beyond his 21 years to survive until the close of play alongside Cheteshwar Pujara (7 no).

India's advantage may have been even greater if not for a lifeline to Labuschagne that proved one of the biggest talking points of the day.

The Aussie batsman looked for all money to be walking back to the pavilion after being given out LBW, only to successfully challenge the dismissal.

DRS showed the ball was pitching in line and impacting the Aussie's pads in line, only for ball-tracking to mystify most viewers by suggesting that it was clearing the top of the stumps.

Labuschagne was given what could turn out to be a vital reprieve, leaving viewers scratching their heads at the DRS.

“I think ball-tracker had one too many shirazes yesterday. For mine, that was hitting halfway up middle and leg. What is going on there?” Kerry O’Keeffe said in commentary.

Fellow commentator Shane Warbne also couldn't believe Labuschagne hadn't been given out.

“I thought he must have hit it because he went upstairs so quickly. I can’t believe this was going over the top of the stumps," Warne said.

“Look where he is, it’s on the knee roll, he’s down crouched as well, I thought at worst case it would have been just clipping leg-stump, got some part of legstump and he’d be on his way.

“But the bounce here at the MCG that we’ve seen off the quickies, it’s continuing off the spin which is making life difficult for batting.”

It was a sentiment shared by many viewers on social media.

India thrive in tricky MCG conditions

The MCG pitch has been infamously flat in recent years, but quick Jasprit Bumrah (4-56) and spinner Ravi Ashwin (3-35) took advantage of its pace, spin and bounce for India.

Apart from an 86-run fourth-wicket stand between Labuschagne and Travis Head (38), Australia never looked comfortable as Bumrah, Ashwin and debutant Mohammed Siraj (2-40), heaped on the pressure.

Bumrah cleaned up Joe Burns in the fourth over, before Ashwin claimed makeshift opener Matthew Wade (30) and the prized scalp of Steve Smith in an eventful first session.

Smith was caught at leg-slip off a turning delivery without scoring - the 31-year-old's first Test duck since 2016.

Bumrah had Burns nicking to recalled wicketkeeper Rishabh Pant for a duck, again ramping up pressure on the Queenslander's international future.

Labuschagne successfully appealed an lbw decision and was struck on the helmet, resulting in a lengthy delay, during his innings as he top-scored with 48.

He lamented up to three "frustrating" dismissals but Labuschagne admitted he was unsure what a par-score was on the wicket.

"You know you're going to have to lock in and bat for a long period of time ... this is the art of Test cricket, this is why we all love it," he said.

"It's a continual challenge for bowlers to come up with new ideas to stop batters scoring and that's what (India) did."

Captain Tim Paine was at the centre of some controversy, surviving a contentious run-out decision on six, with many experts believing his bat was behind the line.

But the third umpire's call didn't cost India, with the Australia wicketkeeper dismissed shortly after for 13.

with AAP

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