Kevin Pietersen's zenith as a Test batsman arguably came in the summer of 2006, the last time Sri Lanka were the visitors to these shores. In consecutive Tests at Lord's and Edgbaston, he monstered an attack that still included Muttiah Muralitharan for consecutive innings of 158 and 142, and in so doing unfurled a repertoire that took the breath away. Amid all the flamingo flicks and bludgeoning straight drives that lit up his performances, no single blow was more extraordinary than the switch hit for six with which he dispatched Murali into the Birmingham suburbs.
Better still than the stroke, however, was the manner in which Pietersen justified his apparent recklessness in his press conference at the close of play. "To understand that shot you need to know that I had just come down the wicket to Murali three times," he told the assembled reporters. "I had hit him over mid-off for four, through mid-off for four and then I had cut the doosra for four. Murali moved his mid-off and mid-on back and put men at deep square leg and cow corner. All my options had been blocked." And therefore, once again, necessity proved to be the mother of invention.
Fast forward five years, and Pietersen once again found the Sri Lankan attack to his liking, as he launched into his most fluent innings on home soil since his captaincy summer of 2008. If his 72 at Lord's had been a harbinger of good times to come, then Saturday's 85 from 115 balls at the Rose Bowl was vivid confirmation that his mind is back where it belongs. Even the manner of his downfall was strangely reassuring, as he baulked at the notion of shutting up shop for the night, and carried on climbing into his strokes with the alacrity of old.
That he failed to reach his 18th Test hundred, and his first in England for three seasons, was on the face of it less relevant than his willingness to trust his talent to the max, in the same wholehearted manner that used to enable him to gallop through to century after century with scarcely a pause for thought. "Actually it wasn't frustrating at all," he said of his demise with nine balls of the day remaining. "To play the way I've played today has given me a lot of happiness. The hundreds will come - and a lot of them, I hope."
The only intriguing difference between the Pietersen of then and now was his determination to play within certain self-imposed limitations - not his limitations per se, because as he has shown on numerous occasions in the past, he doesn't have any scoring areas that are strictly off-limits. But the single most alluring feature of his innings was the quality of his straight driving, Twelve of his 14 fours were belted in the arc between extra-cover and mid-on, including his third ball of the day, off Suranga Lakmal, and his first from the slow-left-armer, Rangana Herath, who plopped down one more ball before lunch and was not then seen again until KP had 69 runs to his name.
"To have gone back to basics and hit the ball straight and keep penetrating the opposite stumps, for me that was brilliant," he said. "I had three or four scoring areas I've been really working hard on. One of them was the ball that got me out, the half-volley under the eyes which I was looking to hit through extra-cover, and then there was hitting it down the ground, and then short balls I looked to score off.
"Those are the few areas I looked to score well off. The rest I wanted to bat time and be patient," he added. "I was lucky enough, on a very good wicket, to have played like that. I just did exactly what I'd done the whole time I batted - if it was in my areas, a half-volley out there, I hit it, because point was really far behind. All I needed to do was hit it through extra-cover and pick up some more runs for the team."
He was not at his most forthcoming when speaking to the media afterwards - the mere mention of the name "Herath" made him bristle like Pavlov's dog - but the manner in which he broke down the approach to his innings had distant echoes of that 2006 performance. At any rate, it confirmed the extent to which he is thinking about his cricket again, a crucial factor that has not always been taken for granted of late, certainly not when he slashed his way to five runs in two innings in the opening half of the series.
"I've been promising it for a while," he said. "Lord's was nice, second innings, to get in there and start feeling like I normally feel when I go out and bat. There were a frustrating couple of ways I got out in the first two innings of this series, but I really, really enjoyed the way I played today. They bowled pretty straight to me, and I was lucky enough to line it up really well."
And yet, for all his bravado about missing out on a century, one senses that Pietersen will not fully relax until he has shrugged that monkey clean off his back. It irks him that his career-best 227 in Adelaide - the innings that set up the victory that set up the Ashes, no less - is generally regarded as an anomaly, and that was a point he reinforced when he reminded everyone of his other performances in Australia. "I made 50-odd in Melbourne, then 30-odd in Sydney, then pulled one down fine-leg's throat," he said. "I've not been playing badly; I've just got myself in and then out occasionally."
As for that unmentionable issue against left-arm spin, Pietersen was unequivocal - even if he was slightly unsure of what he was being unequivocal about. "You guys seem to have a problem with that - I don't," he said. "We realise you guys have got a job to do, and if I give you ammunition you're going to fire the gun.
"I've probably given you enough ammunition - they've got me out quite a few times, but that's the nature of the beast, but it's absolutely no drama to me. What it's probably made me do is play them a lot better than I would have - because I've worked that extra bit harder, thinking 'Have I got a problem ... I've never had a problem with them'."
As it happens, Pietersen's innings made him the second former Hampshire player to make his mark on this contest after Chris Tremlett's six-wicket haul in Sri Lanka's innings, though given how rarely he appeared for the county, and how acrimonious his eventual departure had been, this hardly counted as a homecoming performance.
Still, trust KP to see things differently. "The reception was fantastic, though I don't see why it would be frosty," he demurred. "I just changed county - which I'm sure hundreds and thousands of cricketers have done before."
The pretensions and contradictions are all part of the fascination of KP, but he's never better than when he's sure of his aim. In that regard, there's an awfully long way to go until he scales the heights of invulnerability he enjoyed when Sri Lanka were last in town - and given that there was a time in that summer when many doubted that he had a single chink in his mental armoury, he might never touch those heights again.
But this was undoubtedly a step in the right direction, as a Rose Bowl crowd who had lost two prime hours in a soggy afternoon session were treated to some richly appreciated pyrotechnics. When the man is in full flow, there are few better sights in the game.
Andrew Miller is UK editor of ESPNcricinfo