David Warner shapes to defend Mitchell Starc, misses, and the plastic stumps in the Headingley nets go flying. All manner of dismissals take place in the nets, real or imagined depending on the fields "set" by the bowler or throw-downer, but few quite so dramatic.

The moment rather summed up Warner's Ashes tour thus far, in which he is yet to reach double figures across four knocks. Married up with his closing three innings in South Africa prior to the Newlands scandal ban, Warner is in the second longest streak without a half century of his career - his worst run was eight innings in New Zealand and Sri Lanka in 2016.

At Edgbaston and Lord's, Warner's rapid exits were somewhat less of an issue for Australia, bolstered as they were by the genius of Steven Smith. But with Smith out of action in Leeds due to concussion, the tourists' batting stocks have been made to look exceedingly thin. More than ever, Australia need Warner to find something. The captain Tim Paine is hopeful that Warner will do so this week, referring to Smith's absence as the "poke and prod" the opener needs.

"David, I've spoken a lot about the fact he averages close to 50 in Test cricket and he's done that over a long period of time," Paine said. "I think with Steve missing this game, it might be the little poke and prod Davey needs. He likes that responsibility and my experience with Davey is when people doubt him and his back is against the wall he comes out swinging. I'm expecting the very best David Warner this week."

How Warner finds his best is somewhat complicated by the way he has approached this tour. For so long a combative, aggressive batsman, his stated goal in England this time around was to calm himself, slow his tempo, and find a balanced rhythm at the crease more sustainable over long innings. During the World Cup, the method worked to a reasonable extent, as he peeled off centuries against Pakistan, Bangladesh and South Africa.

"My experience with Davey is when people doubt him and his back is against the wall he comes out swinging. I'm expecting the very best David Warner this week" Tim Paine

But in the semi-final against England he was swiftly beaten by a sharply rising delivery from Chris Woakes, and so far during the Ashes has been found wanting in terms of defensive tightness and decisiveness at the hands of Stuart Broad and Jofra Archer, both pursuing a rigorous line at him from around the wicket. It is a method seldom seen against Warner - Broad has admitted he had previously thought primarily about finding Warner's edge rather than constraining him by targeting the stumps - but it is proving fiendishly effective.

One close observer of Warner has been England's captain Joe Root, who has marshalled the plans against the left-hander while also mired in his own poor run of batting form. How does Root think a player struggling for runs can find rhythm and confidence again? It starts with honest self-assessment.

"You need to be realistic about how you are getting out. And be fair," Root said. "Sometimes as hard as it might be you have to give credit to the opposition when they've bowled some good balls. You don't want to be over-critical when you don't need to be. But there are times as well when you got to understand when you got it wrong. And then work it back from there. You don't become a bad player overnight.

"You don't lose the runs you've scored already. And you know you've got it in the bank and you've proven it before. From my point of view, I have got Ashes hundreds in there in the bank and I know and I know what it takes to win games of cricket. Of course from Dave's point of view, we'll be trying to keep him to single figures for as long as possible because he's a proven performer for Australian cricket."

An intriguing returning presence around the Australian side will be Ricky Ponting, who commented during the Lord's Test that Warner need to be showing more positive intent to score. Certainly, this is the view of Warner's longtime batting coach and sounding board Trent Woodhill, who has always focused on the 32-year-old's ability to put bowlers under pressure, leading to fewer deliveries challenging his defence, rather than trying to make him "tighter" or able to bat for longer periods.

Most of Warner's most memorable and impactful innings have been extraordinarily bold in their strokeplay, and it is difficult to see how, given his current struggles in defence, how he will be able to score runs without at least reverting to a more aggressive posture, eyeing off the smallest errors in line or length to pick off. Another window into Warner's state of mind has been the fact that, at slip, he has struggled to hold catches so far - being a primary offender among the five chances put down at Lord's. In a vote of faith, Paine reckoned Warner would be staying in the cordon.

"I think Davey will probably stay in there, and Marnus - for people who haven't seen him - he's probably as good a slipper as there is going around," he said. "And everywhere else in the field, so he'll cover Steve with the fast bowling I think at second slip, and then we have Usman Khawaja who did pretty well in Australia last year for Lyno [Nathan Lyon].

"So we've got a few options there, we've got Matthew Wade who's a wicketkeeper and he can field anywhere. So we've got a number of options to go through that spot if we need to. But I expect Davey to go back there, he's allowed to have a bad day."

That, as much as anything, will be key to Warner finding the runs Australia so dearly need from him at Headingley. Just as he responded to Starc's stump rattler by calmly picking up the broken wicket and resetting for the next ball, Warner needs to put the Edgbaston and Birmingham dismissals out of his mind and strike a blow when battle is rejoined in Leeds. The incentive, to be a key player in the Test match that sees the Ashes retained by Australia, is enormous.