Australia have been denied the wicket of Virat Kohli on the opening day of the fifth Test in controversial circumstances.

It took only eight overs for the decisive Test of the Border-Gavaskar Trophy at the SCG for the fuse to be lit, as Australia believed they had taken a miraculous catch that would have left the visitors reeling at 3-17.

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Kohli edged a Scott Boland delivery through to slips where a diving Steve Smith got a hand to it before it ballooned up to teammate Marnus Labuschagne to complete the catch.

The catch sent the SCG crowd into raptures, with the Australians running the length of the wicket in their celebrations.

Australia continued to celebrate with initial replays showing Smith’s fingers under the ball. But another angle appeared to show the ball briefly touching the ground.

The third umpire ultimately said the ball touched the ground and ruled it not out, which left Smith and the Aussies fuming.

“He’s got his fingers here but like it rolled onto the ground. Yeah, that ball just touching the ground,” third umpire Joel Wilson said.

Australian captain Pat Cummins sought clarification from the on-field umpires as Kohli fought on for the tourists, who had won the toss and opted to bat.

Channel 7 commentator Justin Langer believed it should have been given out.

“In my opinion, from what I have seen there, that makes it more obvious that should have been out. Steve Smith had his fingers, you could see he was flicking the ball up, brilliant what he did. To have his fingers under the ball, flicked it up deliberately. In my opinion, that’s out,” he said.

“As Simon Taufel said, his fingers were under the ball. Looked to me as if he was instinctively looking to flick the ball straight up. In my view the finger was still under the ball, that should have been a great catch for Australia.”

Ricky Ponting believed it should have been a catch despite the ball touching the ground slightly.

“They have actually just changed that interpretation in the last couple of years. If you remember back to Lords, and Mitchell Starc’s catch, where he took the catch high above the ground, controlled the ball, but when he hit the ground, the ball went along the surface that way – so his hand and fingers were on top of the ball,” Ponting said.

“That was deemed to be potentially keeping the ball in your hands. So, they then had it with the fingers underneath the ball, as that one was, you can see his fingers clearly underneath the ball. And then Joel said that it rolled out the side, touched the ground, but as far as I was concerned, if it had have come out of his hand, he wouldn’t have been able to scoop it up. The ball would have just rolled away to the side if the ball came out of his hand. I think he still had control of the ball, even though the ball had touched the grass.

“There’s doubt there. But that’s why we have technology. That’s why we have a third umpire, to actually get to the bottom, to make the right decision. Now if you read the interpretation and the laws, I’m not sure we got the right decision there.”

Smith was “100 per cent” certain he got his hands under the ball, but accepted the decision.

“No denying it whatsoever, 100 per cent, but umpire’s made the decision. We’ll move on,” Smith said before the lunch break.

Former umpire Simon Taufel said you could make a case either way.

“I think you described it very well when you said that depending upon which side of the fence you sit on, you could probably build a case for either decision to be given. Listening to Joel Wilson’s language there, when he said the fingers were underneath the ball and then he’s seen it roll onto the ground, by his own language he is telling us that he believes he’s seeing that ball on the ground,” he said on Channel 7.

“So, there are two things that the TV umpire here is looking for. One is fingers underneath the ball. He was satisfied there. But then he believes through those pictures that he’s clearly seen the ball on the ground. And here’s the challenge slowing it right down with super slow-mo. Play it at real speed and it looks pretty good.

“I can certainly understand what the third umpire’s done there. He believes he’s seen the ball on the ground and called it way he’s seen it. Normally the ICC protocol on fair catches is if you see the fingers underneath the ball, that’s good to maintain a fair catch. The problem is the on-field umpire’s no longer have the soft signal and make the decision. It’s purely in the hands of the television umpire now.”

Indian great Sunil Gavaskar sided with the third umpire.

“He wasn’t able to control it and then I think the ball slipped out just a little bit and grazed the ground. That is what the TV evidence showed,” he said on Channel 7.

The decision quickly divided fans and experts, although it appeared the majority thought it should have been out.

Former Indian captain Kohli would have breathed a sigh of relief after the decision, having averaged only 12.4 across five innings since an unbeaten century in the series opener.

Kohli had been the subject of scrutiny during the MCG Test for making shoulder contact with debutant Sam Konstas between overs during the opener’s first stay at the crease.

He also raised eyebrows for confronting a journalist earlier in the series to warn against filming his family members.

Kohli survived until lunch as Shubman Gill was caught at slip off Nathan Lyon for 20 on the last ball of the first session to leave the tourists 3-57.

After claiming captain Rohit Sharma had “opted out” of the match, India won the toss and batted in Sydney but immediately had three balls beat the bat in the match’s second over.

KL Rahul clipped Mitchell Starc straight to Sam Konstas at square leg on four, before Scott Boland angled one across Yashavi Jaiswal and drew his edge on 10.

India then looked at risk of slipping to 3-17 when Kohli edged Boland in his first ball, before being handed the reprieve.

Kohli and Gill put on 40 for the third wicket, before the latter jumped down the pitch to Lyon and edged him to Smith at slip on the last ball of the session.

The tourists must win the final Test in Sydney in order to retain the Border-Gavaskar Trophy, with a draw at the SCG enough for Australia to clinch a 2-1 series victory.

Kohli looms as their biggest hope.

While his second-innings century in the opening Test in Perth has been his only score above 40, Kohli has long stood up on big occasions for India.

After putting his cover-drive away for the most part in Melbourne, the right-hander’s first two scoring shots on Friday came to balls outside off stump.

He has been watchful since, playing 14 straight dot balls just before the break with Australia debutant Beau Webster bowling a stump-to-stump line.

A series win over India would hand Australia back the Border-Gavaskar Trophy, and mean Pat Cummins’ side hold every bilateral Test series trophy available to them.

A win at the SCG would also be enough to ensure qualification for the World Test Championship final against South Africa at Lord’s in June.

– With AAP