A disastrous DRS misunderstanding between Australia's captain Steven Smith and the No. 4 batsman Shaun Marsh helped set them on the path to defeat in Bengaluru, one that allowed India back into a bare-knuckle fight for the Border-Gavaskar Trophy.
Twice Smith appeared to have established useful stands in pursuit of a target of 188 for victory and an unassailable 2-0 lead in the four-match series, first with David Warner and then with Marsh. Warner was lbw to R Ashwin while attempting to sweep, and on review was found to be have been struck in line with the stumps by the barest possible margin, therefore upholding the decision.
That left Australia with a solitary review when Marsh shouldered arms to Umesh Yadav's delivery from around the wicket and was hit on the pads in the vicinity of the off stump. After Nigel Llong raised his finger in response to the appeal, the two batsmen got together to chat about using DRS.
"We weren't entirely sure," Smith said. "I sort of said "go" as in "go have a look at it" and he sort of turned around and started walking, so I should've probably put my hands up and done it."
HawkEye showed the ball wouldn't hit the wicket and Smith admitted it had been an unfortunate way to lose a batsman who had been in good form. "Obviously we saw the replay and it was missing the stumps so it would've been a nice one to review," he said. "It perhaps could have been important. Shaun was looking pretty good. It was a disappointing wicket at the time, but that's the game of cricket, you have to move on and try and do what you can from there."
Marsh's dismissal left Australia with only two specialist batsmen in Smith and Peter Handscomb. After they were separated by the captain's subsequent lbw, the end came quickly, exposing the limitations of Mitchell Marsh, Matthew Wade and the tail on a fiendishly difficult pitch and handing the match to India by a more comfortable margin than what seemed likely for most of a very memorable Test.
"On a day four wicket that's pretty challenging, you need a few things to go your way, you need a bit of luck and today wasn't our day," Smith said. "We competed very hard, this morning we bowled well and got the breakthroughs we needed to and got ourselves batting, but 188 was always going to be a difficult task. We probably just needed one or two batsmen to stand up a little bit more and try to get us close to that score."
In assessing where the visitors lost the thread of a contest they had begun in fine style on day one after losing the toss, Smith pointed to shortcomings in their bowling in the second innings. Rather than being patient - a quality they showed in spades throughout the first day in Bengaluru and throughout the first Test in Pune - Smith conceded his men had rushed a bit. By the time they regained the right tempo, India's lead was past 150.
"I think when we came out and bowled we were probably rushing a little bit, almost expecting things to happen instead of getting to the basics and executing our skills," Smith said. "We were a little bit off with our lines and lengths, gave them a few too many freebies in the first innings as well.
"On this wicket, it was about maintaining your line and length and letting the wicket do the work. There was a lot of natural variation in this game and at times we got a bit too wide or a bit too full and we weren't able to continually hit those areas we were able to hit and that relieved the pressure [off India] a little bit.
"What we did this morning was what we needed to do yesterday, and if we did that, things could certainly be different. But credit to the way the guys came out and did it today, 188 was always going to be a difficult task. Ashwin went to work on a wicket that was certainly suiting him and their quicks bowled in some very challenging areas."
Australia must now overcome the mental hurdle of losing a match they had made much of the running in. "It's disappointing but I'm still proud of the way the boys competed," Smith said. "When we came over here we were written off and expected to lose 4-0 but the boys have competed incredibly hard over the last two Test matches, so if we can continue to do that then hopefully we can get some more results go our way."
Daniel Brettig is an assistant editor at ESPNcricinfo. @danbrettig