Four summers ago, Australia returned home from a draining double tour of the West Indies and England with the evident need to regenerate their team, particularly in terms of batting. The retirements of Michael Clarke, Chris Rogers, Brad Haddin and Shane Watson left a large hole in the line-up, but the national selectors had two paths down which they could go.

One would have been to invest very much in youth, surrounding the new captain Steven Smith with a group of his own generation and affording them the chance to develop together in Test series against New Zealand and the West Indies that represented strong competition but nothing like a bout against England, India or South Africa.

Instead, the panel chaired by Rod Marsh went for a hybrid of youth and experience, picking Joe Burns, Usman Khawaja and Mitchell Marsh and retaining Adam Voges and Shaun Marsh. Batting around Smith and David Warner, all enjoyed productive summers, as Australia enjoyed three series wins and, at summer's end in New Zealand, the brief pleasure of the No. 1 ranking on the ICC table.

Yet when that moment in the Christchurch sun was followed by five defeats in a row against Sri Lanka and South Africa, another rebuild was swiftly called for after Rod Marsh's resignation and Smith's public statement of embarrassment at the team's performance. The mountains of runs made at home the summer before were made to look not only hollow, but something of a waste: Voges' anomalous Test batting average of 61.87 stands as a monument to the tack taken by the selectors.

ESPNcricinfo Ltd

This time, the retention of the Ashes in England for the first time since 2001 was cause for celebration, but Australia still aren't sure of their best top six. A 2-2 scoreline in which Smith's feats more or less carried the batting line-up, brought both the urn and plenty of considerations for the selection chairman Trevor Hohns and the coach Justin Langer - right now, the only two members of the national panel.

If Warner, revitalised by a high-quality hundred at the Gabba in the opening Sheffield Shield round, takes his place alongside Smith and the two other best Ashes performers in Marnus Labuschagne and Matthew Wade, then there are two spots up in the air. An opener and a middle-order player. Last week's centurions included Alex Carey and Will Pucovski, who would both represent more future-focused selections, while Burns, a reborn Nic Maddinson and the Ashes incumbent Marcus Harris also made runs.

Apart from Smith and Warner, no-one possesses a better record in home Tests than Khawaja, and he has the capacity to both open or bat at No. 3. Similarly, Burns has made centuries for Australia both at the top of the order and in the middle. Then there's Travis Head, vice-captain of the Test team until he was dropped for the Oval due to a desperately poor record against balls angled into him from around the wicket. Mitchell Marsh's broken hand also means there is no allrounder particularly likely to press for the No. 6 berth ahead of captain Tim Paine.

Usman Khawaja poses at the toss Getty Images

Darren Lehmann was a selector as recently as April last year, when the Newlands scandal brought an abrupt end to his stint as national team coach. Asked to name his top three for the first Test against Pakistan at the Gabba, he was succinct. "Warner, Burns, Marnus are my top three, Smith at four," Lehmann said.

"Warner definitely. His record in Australia is unbelievable, he got a hundred here at the Gabba in the Shield game and I thought he batted beautifully. Obviously got a first baller in the second innings but he played well. I like Burns, because I just think Burns' Test record is pretty good and he needs another opportunity. Uzzy and Burnsy are the ones fighting for one spot aren't they? That's the thing at the moment for them. Uzzy's a class player, his record in Australia is exceptional as well. A lot will come down to the next couple of Shield games actually.

"He could easily open and Joe could bat down [the order], they could easily do that as well. It depends on the make up the selectors want, I suppose. It's a good thing when you see so many young guys making big runs. The Junction wicket was quite flat last week, but I think the best hundred of the round would have to be David Warner's at the Gabba and then Perth had a bit in it as well. Tim Paine to get a hundred looks like he's in good form, Carey got a hundred, so a lot of players making runs, which was pleasing."

Khawaja was not one of the players fortunate enough to put their name in lights in round one, pinned lbw by Harry Conway from around the wicket on day one and then wafting outside off stump to edge Sean Abbott behind in the second innings. Always at pains to indicate he is not getting ahead of himself in terms of thinking about international matches while the task of leading the Bulls is his job this week, Khawaja did note however that early season Shield games with Test selection in the air tended to be especially willing.

At the same time, he also observed that runs at the Gabba needed to be given plenty of currency relative to those scored at other venues. There could be little comparison, for instance, between the hundreds scored at Junction Oval and Warner's singular effort in Brisbane as the ball seamed, swung and bounced. To that end, A century for any one of Khawaja, Burns, Head or Carey in Queensland's meeting with South Australia could vault them above numerous other contenders. Doubly so given that Hohns has chosen to watch the Gabba match this week.

"If a team bowls well at the Gabba there's not much you can do," Khawaja said. "You can't bully attacks at the Gabba, can't get on the front foot and drive on the up and do the other stuff you can do in other states when the ball gets a bit older. It's a lot more of a patience game, especially the way the wicket was last week and the weather around made it a little bit tougher too.

"So it always means more, the WACA can be a bit like that too when it's swinging around, so hundred is a hundred anywhere, but when there's a result on the line it just means that much more. Every game is a big game of Shield cricket, both individually and as a team, especially when there's Test series coming up, spots up for grabs.

"So I'm sure all the guys will want to do well, bowlers are wanting to do well, batsmen are wanting to do well, but for us as a team, the main focus is trying to play as a team, trying to do what we can for the team. That usually involves batters scoring as many runs as they can and bowlers taking wickets and being patient. If you do that as an individual and take care of that, the team stuff takes care of itself too, so it's a bit of a circle."

Four summers ago, Khawaja took his chance to have a breakout summer that has kept him on the international scene more or less ever since. In 2019, as Hohns and Langer weigh up whether to mix youth and experience or rebuild the batting order ahead of future overseas challenges in South Africa, India and ultimately England again, opportunities beckon for those steady enough to show their best attributes with the eyes of the selectors squarely on the Test top six.