That was then, this is now for Steven Smith

It was the first ball of Moeen Ali's fifth over, and Steven Smith's eyes lit up. He picked the length early, and crashed a half-volley into the off side. His timing was crisp, his front elbow high. Harry Brook flung himself low to his right at short extra cover, and deflected the ball straight to mid-off.

Four years ago, this shot would have brought Smith four runs. That 2019 summer, Smith scored 774 Ashes runs in his first series back after a year-long ban, 333 more than anyone else on either side. He was the protagonist of Australia's success: constantly batting, constantly scoring runs, constantly grinding England down.

But that was then, and this is now. Smith is back in Manchester, the scene of an epic double-hundred in 2019, and he is battling against a revitalised England team - and against himself. He has been in this country for nearly 12 weeks and a tour that started with a few low-key weeks at Sussex, a century in the World Test Championship final and another at Lord's is beginning to drag on for him.

Smith played his 100th Test match in Leeds, an occasion that he found mentally flattening. When he spoke to the Unplayable podcast at the start of this week in Manchester, he explained that the attention around his landmark forced him to zoom out and think about his career as a whole, obscuring his usual focus on his batting. He made 22 and 2, and hated every minute of it.

In his first innings here, Smith might well have been out to the first ball he faced. Chris Woakes dug one in short, which he swivel-pulled out into the deep on the leg side. Mark Wood, who was five yards in off the long-leg boundary, flung himself high to his left. If he had been on the rope, he would have taken the catch; instead, Smith picked up four.

For the next 45 minutes, Smith batted like his old self. When Stuart Broad went wide outside off, Smith flogged him through cover-point; when Broad went straight, Smith whipped him away off his pads. He swiped Moeen down the ground for six over long-on, and by lunch, he had 33 off 34 balls. He was like an inverse Ronnie Corbett, pre-empting every question that England asked.

But 17 balls and eight runs later, Smith was out. He was trapped on the front pad by Mark Wood and, after being given not out on field, was lbw on review. Smith is hardly unique in preferring fast-medium bowling to genuine pace but he was rushed by Wood and late on his shot, shuffling across and shaping to work through wide mid-on. He was one of four Australian batters to reach 40, but none managed more than 51.

Smith has spent most of his Test career fielding in the slips, but has found himself on the boundary at deep backward square leg for much of this series. As England racked up 592 across the second and third days, he lurked on the rope while copping relentless abuse from the crowd, occasionally flinging himself one way or the other to try and cut off yet another boundary.

The Hollies Stand's chant on the first day of the series at Edgbaston - "We saw you cry on the telly" - has followed Smith around all tour; on Friday, fans in one stand reminded him: "You're not captain anymore." Smith has developed a thick skin over a 15-year professional career but there is no way that the barrage which he has received over the last five weeks cannot have affected him.

It is long established that Smith struggles to sleep during Test matches - in 2019, he estimated that he sleeps for "15 to 20 hours" per Test - but his record in the third and fourth innings is only getting worse. Since the start of the 2021-22 Ashes, Smith has averaged 20.84 in his second innings of a Test with a top score of 35 in 16 attempts.

On Friday, he edged the second ball he faced towards Joe Root at slip, who seemed unsure whether or not it had carried to him; TV replays were inconclusive, and Smith was given not out. He shrugged towards England's fielders, and was soon back into his usual twitchy rhythm, stepping across his stumps to punch, whip and flick.

But after Brook's dive cut off his drive, Smith found himself confronted with Wood's pace once more. Wood went wide on the crease, and Smith swivelled him away through the leg side for one; back on strike two balls later, he went wide once more, angling a cross-seam short ball in towards his ribs.

Smith's shot was neither one thing nor the other: neither a full-blooded pull, nor an attempt to knock the ball on its head for a single to the sweeper. It betrayed his mental fatigue, swamped by the context of the game and by a head-to-head battle he was so desperate to win that he never gave himself a chance to.

A tickle of Smith's glove flew through to Jonny Bairstow, and he marched straight off. Wood held his arms wide and threw his head back, engulfed by his team-mates as the fans in the temporary stand behind him rose to their feet. Smith held his bat in his right hand and mimicked the ball's trajectory with his left, as though to confirm he had been deceived by the variable bounce.

He faced 14 balls from Wood in this match, and was dismissed by two of them. Since his hundred at Lord's, he has made 116 runs in five innings. He has 248 across the series at 31.00, 45 fewer than he managed in Manchester alone four years ago. Smith is no longer an outlier, simply part of the pack.

England still celebrate his dismissals like he is the Smith of 2019, but the Smith of 2023 is a different, altogether more human cricketer. He is 34, closer to the end of his career than the start. He will not be back here in four years' time; he seems to have realised his own mortality.

Two months ago, Smith spoke about his bucket list, and the prospect of finally ticking off an away Ashes win. Whether or not Australia escape this Test with a draw, he only has one more week to make that happen.