The beers were being cracked, and so were the smiles. There was Matt Renshaw, mostly recovered from concussion, grinning from ear to ear. There was Peter Handscomb, who could barely have made a stronger start to his Test career. And who's that other young bloke? Oh, that's Hilton Cartwright, barely identifiable to many Australian cricket fans a week ago, but forever the owner of baggy green number 450.

There too was Matthew Wade, not celebrating his first Test series win like the aforementioned trio, but his first in four years. There was Steve O'Keefe, who has now played four Test matches but never two in the same series, and who at 32 is the oldest man in the team. There was Jackson Bird, the 12th man, who in this match equalled the all-time Test record of four catches for a substitute fielder.

And there, as Mark Taylor roamed the Australian rooms with a Channel Nine microphone, were the familiar faces: Steven Smith, David Warner, Mitchell Starc, Josh Hazlewood, Usman Khawaja, Nathan Lyon. All members of a side that, only eight weeks ago, were humiliated in Hobart, skittled for 85 by South Africa. That was a nadir that brought sweeping changes from Australia's selectors, and the result was a sweep of a different kind: 3-0 against Pakistan.

And while Smith's new-look team deserves the chance to celebrate, there must be caveats. Pakistan entered this series having lost nine consecutive Tests in Australia, a streak that has now extended to 12. For Pakistan, touring Australia is a daunting prospect. And Australia, though they played well in this series, now face a similarly intimidating tour of their own: four Tests in India.

Australia's recent record in India is little better than Pakistan's in Australia: they have lost their past seven Tests on Indian soil. And they will embark on next month's tour with certain questions still unanswered.

Who, for example, is their preferred Test allrounder? Mitchell Marsh started the summer in the position but lasted only one Test. The selectors reverted to a specialist No.6 batsman, Nic Maddinson, who made 27 in four innings. On debut in Sydney, Cartwright showed encouraging batting signs, driving his first ball in Test cricket through cover for four on his way to 37.

But Cartwright's balls were sluggish, and not just after he was struck a low blow at short leg. He delivered only four overs in this Test and barely broke the 125kph barrier. It is hard to imagine him worrying batsmen at that pace. Marsh and Shane Watson at their quickest have both operated above 140kph.

Even Wade, the wicketkeeper, has been clocked at over 130kph when sending down medium-pacers. But Wade's work behind and in front of the stumps is Australia's other major question-mark. He was brought into the side to replace Peter Nevill, mostly because the selectors decided Nevill had not made enough runs.

But in the four Tests since his recall, Wade has managed only 50 runs at 12.50. Nevill, by comparison, made 60 not out only two Tests before he was axed, singled-handedly giving Australia a chance of saving the Perth Test against South Africa.

Wade's work with the gloves has been far from flawless, either. He dropped Younis Khan in the first innings in Sydney, missed a stumping chance against Sarfraz Ahmed in Brisbane, and failed to move for what appeared to be his catch in Adelaide when Hashim Amla edged between the keeper and first slip. Nevill makes mistakes, too, but his glovework is generally superior.

But if these are the unanswered questions, at least two have been answered emphatically. Australia wanted an opener and a No.5, and they found them. Renshaw is only 20, but showed remarkable maturity to bat throughout the first day at the SCG - while Warner was smashing a hundred in a session, no less - and fell only 16 short of a double-century.

Showing the same resolve against India's spinners on turning pitches will be a vastly different challenge, and it remains to be seen how Renshaw will handle it. So too Handscomb, although the way he used his feet to both advance and play back against Yasir Shah during this series was encouraging. Handscomb scored two hundreds in the series, and has not been out for less than 50.

All in all, it has been quite a turnaround. Of course, it is hard not to feel for men like Callum Ferguson and Joe Mennie, who debuted in Hobart and were discarded as part of a total selection rethink. Hobart was Australia's nadir - rolled for 85 and 161, and losers by an innings and 80 runs - but from the next Test in Adelaide until now, they have been unbeaten.

"It was pretty tough times, to be honest with you," Smith said after the win in Sydney. "You lose your first two Tests of an Australian summer and you're not in a good place. It wasn't great times. But I'm really proud of the way the guys have come in and turned it around since then. I think we've played some very good cricket and that's the kind of cricket I want us to play. I'm really pleased for everyone that's been involved.

"When we all got together as a group and trained for the first time in Adelaide, straight away I felt a shift in attitude and energy and enthusiasm amongst the group. I guess we were able to put all of that out into the middle and get the performance we were after."

Bigger challenges lie ahead. The biggest, in fact. But for now, the beers and the smiles are well-deserved.