From Root's call at the coin toss to send Australia in, to Smith's move not to bowl again at England on the the third night, the second Test that is shaping up as an unlikely thriller has been all about the two teams' respective captains.

Smith, a runaway man of the match in the first Test, has found little going his way since he opted against the follow-on without consulting his bowlers. The Yorkshireman, meanwhile, has a chance to conjure a miracle.

Whether the match would have already been over had Smith sent England back in no one will ever know but Australia's bowling coach David Saker admitted on Tuesday night that the decision was one they now regretted given the way the game had transpired.

"In hindsight it probably is, yeah," Saker said. "Steven obviously made the decision that he thought the bowlers had bowled enough and that will do.

"We didn't get an opportunity to bowl with the new ball under lights. That was our chance. Maybe we got it wrong. At the end of the Test match we'll review that but if we come out of this winning the game, which I still think we will, you can say it was justified in some way."

Australia will still enter the fifth afternoon at Adelaide Oval as favourites but nowhere near as overwhelmingly so after a gallant Root (67 not out) and Dawid Malan (29) braved a dangerous Nathan Lyon and a desperate home attack under lights to be 4-176 at stumps.

That put the tourists within 178 runs of an England record run chase of 354.

It is nearly a year ago that Australia survived a nerve-wracking finale at the Gabba when Pakistan were close to pulling off a world record fourth-innings chase.

History was also against Root and his men but the bookmakers had their odds plummeting in and their supporters grew in voice with every over.

With Root still in there is hope for England, although a blow was landed late in the final session when Malan was bowled by a pumped-up Pat Cummins, prompting Chris Woakes (5 not out) to walk on as a nightwatchman.

With so much on the line Smith stands to be forever associated with not making England follow on if it turns pear-shaped for Australia on Wednesday but Saker said the captain would be able to put any second thoughts behind him.

"He's a determined guy. He'll think about things tonight, he'll make sure that when we turn up we're right to play," Saker said. "He's obviously frustrated with what's happened but I don't think he's really ruing. Once the decision is made I hope he doesn't think about it too much."

England veteran James Anderson, who had earlier claimed 5-43 as Australia lost 6-67 to collapse for 138 in their second innings, said the visitors had a chance to seize the momentum of the series, in which they trail 1-0.

"It's very rare that a team declares and loses a game so if we can get a result tomorrow it would be huge for a number of reasons," Anderson said. "To be honest we're delighted to be in this position, to have any sort of chance to win this game. It's all we could ask for after the first two days. We need a bit of luck along the way but we'll give it a good shot."

What Australia will have no defence against on Wednesday is an umpiring howler. Smith, as a Generation Y captain, is no stranger to technology but couldn't get it to work for him on Tuesday night. In the the space of three balls he was left without a review up his sleeve and they were reminded of it thereafter by the Barmy Army, who gleefully mocked the Australians with every failed appeal that followed.

Their first review was taken away when Root was on 37 and the Australians strongly suspected he had got an inside edge to a rising Cummins delivery that was gloved by a leaping Tim Paine. The fact the ball clipped Root's pad instead didn't put Smith off immediately arranging his arms in a T shape only moments later when Malan was thumped on the pads by a Josh Hazlewood ball but spared by umpire Aleem Dar.

Not for the first time in this match the ball-tracker had the pink Kookaburra careering over the stumps.If Smith paid the price for being over-zealous, earlier it was Australia's hesitation with the Decision Review System that threatened to be damaging.

In a blunder, they chose not to review an lbw verdict that would have had Alastair Cook on his way off the bowling of Hazlewood for one. As it turned out, the mistake would only cost Australia 15 runs and it was a referral to the television umpire that completed Lyon's key breakthrough against the former England captain.

Smith opted to go upstairs the second time around despite less confidence in the Australian appeal and he was rewarded, as the ball tracker had the sliding delivery from Lyon crashing into Cook's leg stump and he had to go for 16. For Australia, however, that was a rare bright spot on an evening of DRS-induced distress, having broken a 53-run opening stand Cook had enjoyed with Mark Stoneman (36). Root was given out on 32 soon after dinner when he left an over-spinning ball from Lyon that appeared to be travelling towards middle stump, but when the England captain mounted an appeal he, like Malan, was spared by the bounce.

"We got it wrong today without a doubt," Saker said of Australia's use of the DRS. "It's frustrating to not have any [reviews] in the bank coming into the last day, that's for sure."

To make matters worse for Smith himself, he put down a low chance at first slip when Lyon coaxed Malan, on eight, into an edge.