The question marks over Australia's batting line-up go back longer than two months, but their last four matches, of which two have been crushing defeats, highlight the growing problem: in seven innings against Bangladesh and South Africa, there has not been more than one player crossing fifty.

In Darwin, that resulted in a nine-wicket defeat, and in Gqeberha, an innings-and-31-run thrashing. Both of them had defiant second-innings hundreds - Cameron Green against Bangladesh and Travis Head this week - but they stood alone. In the first innings of those games, which is where they were effectively lost, only Steven Smith in Darwin has passed fifty.

"I think it's pretty clear on what we got wrong, we had a pretty s***house day," was Head's succinct appraisal of Australia's 99 all out in the first innings at St George's Park.

Pat Cummins said in his post-match press conference that winning can paper over cracks, and even the two handsome victories - a quickfire two-dayer in Mackay and the impressive performance in Durban - were centred on an individual in the batting rather than a collective.

Mackay looks odd because 210 was enough for an innings win thanks to Mitchell Starc, but Australia's batting stumbled to 146 for 7 with Green the only one to pass fifty. At Kingsmead, Matt Renshaw's match tally of 272 runs stood head and shoulders above his team-mates.

"Think we've spoken as a group going into the series that we've sort of had one individual each time," Head said after his 121 in the second innings in Gqeberha. "They've always been different individuals and we haven't been able to get that collective batting day that we would desire as a team.

"That's what does win you games, individual performance, but as a collective we need to be able to also [do it]. I thought what Baz [Scott Boland] did [40 in over three hours from No. 6 in the second innings in Gqeberha]… was exceptional for the team. A little bit more [of the] supportive roles go a long way, we just haven't been able to find that.

"It's something that the team have been really good at over a long period of time, is being able to build big partnerships, substantial partnerships that win games at cricket. We just haven't been able to find that in the last couple of months. It's very hard to put a finger on why. We're playing some exceptional attacks in some trying conditions but it's not a lack of trying."

However, while Australia have long been a successful team, going back further suggests that partnership batting for the top order is not just a recent issue. From the start of 2024, when the batting order started to be reshaped by the retirement of David Warner, there have only been 11 century stands for wickets one to six. Among the World Test Championship nations, only West Indies have fewer.

After the first-innings collapse for 99 in Gqeberha, Australia's lowest first-innings score since South Africa rolled them for 85 at Hobart in 2016, coach Andrew McDonald bemoaned that the batting order had not been able to soak up pressure for long enough to stem the tide.

"The game's all about momentum," Head said. "Trying to gain momentum, trying to withstand momentum, trying to put pressure back on the opposition and how you do that is in different ways: do you suck back and defend, do you push forward and fight fire with fire? So that's that balancing act.

"Some would suggest sometimes it's not attacking enough, sometimes it's not defensive enough, so it's a two-edged sword with that sort of stuff. It comes down to decision-making, it comes down to a blueprint, it comes down to a plan and a method so when you're tested, that's when your method and your planning and your execution needs to be spot on and when it's not, that's when you see collapses and I think that's throughout cricket forever."

Meanwhile, Head admitted it was clear to see the pressure Marnus Labuschagne was feeling after his reaction to the second-innings dismissal when he lofted Simon Harmer to mid-on to end their 92-run stand. It came just 13 balls after he'd had an lbw decision overturned on DRS with the ball missing leg stump by less than 5mm.

"I've been there before," Head said. "It's a tough place to be when you think you're batting well. I've probably been there more than anyone in my 30s and 40s and feel like you're close and then it's not quite there.

"There's pressure on, it's pretty obvious to see, and obvious in the way he reacts. [He] got away with an [lbw] and you can see… he knows it was a big moment and he's disappointed. Nothing's ever guaranteed in the game, and I can't speak on what happens in the future, but you know he's a good player.

"Test cricket is bloody hard but we're in a performance-based game so everyone feels the pressure. I've felt the pressure over the last couple of weeks, I've been desperate for runs. So everyone feels that no matter what position. Steve Smith's got 11,000 test runs, I reckon he'll feel pressure at some stage. Everyone wants to score runs."