The understudy who became the leading man

At the end of the first Ashes Test match, Marnus Labuschagne had a proposition for Steve Smith. After studying almost every moment of the 30-year old's 144 and 142 at Edgbaston, he wanted some of his bats. Smith was happy to oblige but on the proviso that Labuschagne do something for him in return - clear up his bag after each match, from then until the end of the series.

It would have been fitting if the first use of one of these bats competitively came as Smith's enforced understudy when the former Australia captain failed a concussion test on the morning of the final day. Slightly shaved down and re-stickered, of course. But a quality the pair share is relentless attention to detail. They are the ultimate cricket badgers, and Labuschagne might be the bigger of the two. As good as Smith's sticks might be, he would rather plump for his number one tried and tested.

It's an English term, "badger" - essentially, an anorak but applied specifically to cricket. Someone deeply consumed by every part of it: playing, watching, talking, the way of life. Especially the gear. Labuschagne, like Smith, is a bat geek.

During a first grade match for his club Redlands, based on the outskirts of Brisbane, his teammates wanted to put this to the test. They blindfolded Labuschagne and handed him an array of bats to see if he could determine which was which.

All were once his: with his Kookaburra sponsorship, he gets sent a load and hands out a few to teammates, but keeping the ones he deems perfect. Even with a sense deprived, Labuschagne guessed each bat correctly: his third bat, net bat, the one he gave to Cameron. Of all the players who Kookaburra cater to, he is the most involved during the manufacturing process.

As far as like-for-like replacements go, the only bloke who could have legitimately replaced Smith for talent and worth was born in Cootamundra, 1908, and died in Adelaide in 2001. The man who walked out at 19 for two here, an obsessive right-hand batsman and part-time leg spinner who needed to dig Australia out of a hole, was not too bad a fit, mind.

There are further similarities between the two, beyond the chosen pursuits with bat and ball, and the insatiable love for absolutely all of it. Labuschagne also likes working to leg, and his most notable turns so far in a young career, just five Tests plus this impromptu appearance, have been with his leg-spin.

He also muses incessantly about the game, over-analyses every delivery faced - whether in the nets or a match - and talks to himself constantly while batting. With the first legitimate delivery faced, he took the impersonations too far for Australia's comfort. Like Smith, he was floored by a Jofra Archer bumper.

There was one key difference: the delivery, at 91.6mph, hit Labuschagne flush on the grille, rattling his cage but with enough tensile strength to keep his face, mouth and teeth from harm. Once more, Jos Buttler was first on the scene. Archer continued in his follow-through to check on the felled. But by the time Archer had got there, the batsman had sprung back up to his feet and, following a glove-punch with his partner Cameron Bancroft, shrugged away English concern and began remarking his guard.

The same on-field checks given to Smith were given to Labuschagne, albeit with a lot less fear. All the while, the 25-year old was wide-eyed, imploring the doctor to give him the all-clear. You could tell he was fearful, but not for his own wellbeing or another 92mph snorter. If they could pull out one of the best batsmen of all time, what chance did he have? A contrived Ashes innings could already be taken away from him.

Labuschagne has always grown up looking comfortable against pace, so this was something of a shock. He's more for the dog-slinger than the bowling machine, which as it happens is what domestic and other international batsmen see as the best way of mimicking Archer's shuffle and Indiana Jones whip-crack of an action. The real thing of course, is something different entirely, as he found out.

Once he was given the all-clear, he returned to face up, and played and missed twice. Five balls later against the same bowler, though, one in his half was checked through extra cover for a first boundary. Naturally, a bumper was only two more away. This time, even though the 89mph missile followed him, arrowing in at the mouth once more, he dropped his hands and eyeballed it all the way through to the keeper. The edge was beaten next again. The ball after though run down, soft-hands, head over the ball, to third man for a second four.

After each delivery, Labuschagne walked past Buttler at short leg, returning to his mark after a few words of self-motivation, tossing his bat by the handle from his right hand to his left. He gets into position, patting down four times, shaping up and going again. Even at Lord's, even in an Ashes Test, even on the final day of a match you weren't supposed to be playing in - let alone trying to save - processes are processes.

From then on, there were no errors picking line and, importantly, no further misjudgements on length, beyond a loose attempted ramp shot to start the 21st over. A swept four off Jack Leach - a particular strength of his - took him to 49, with the 50th run ticked off with a dart and push at his 89th delivery faced. A second half-century in the most unlikely of circumstances. One that will go down in folklore. Not just for being Test cricket's first concussion replacement, but for also saving his team when they needed the man he replaced most.

As is Test cricket's way, a newcomer trying to control everything had no control over his dismissal: a well-timed sweep rebounding off short leg and falling perilously close to the ground as Joe Root took the catch.

He stuck around for a little bit longer as the catch went to the television umpire and showed an inkling of doubt. For a moment, he thought he had got away with it, returning to join Travis Head in the middle like a kid thinking he could sneak an extra 30 minutes of television past his bedtime. But by then, he had done enough: 100 balls and 135 minutes taken out of the 48 overs and almost four hours laid down to Australia to save the match. Head ensured he was there to steer the side home, but it was Labuschagne who marshalled them safely through seriously choppy waters.

If there was coincidence around the opportunity, there certainly wasn't for the performance. We are talking about a batsman rich with potential, who has 62 first-class matches and nine centuries. His early-season stint with Glamorgan saw him register 1,114 Championship runs at an average of 65.5. No other batsmen in English cricket has reached four figures this summer.

At the start of the 35th over, Archer came on for his third spell. He had thrown it all at Labuschagne - over, around, full, short. Barring that second-ball biff, nothing had stuck. So he started with a 70.5mph knuckleball, which was patted back to him. Both batsman and bowler, 25 and 24, South African and Caribbean battling for Australia and England respectively, exchanged a glance and then a warm smile. They will do this all again, probably at Headingley in four days time, but definitely in the future, hopefully for a very, very long time.

The Ashes are as they were before this match - 1-0 in Australia's favour. But though we move on from Lord's with a stalemate, we do so with two new gems of Test match cricket.