Hampshire 322 for 8 (Prest 102*, Harmer 5-143) and 267 for 7 (Dawson 119, Vince 89) beat Essex 447 for 9 dec (Rossington 104, Critchley 99, Harmer 62, Yadav 51, Westley 50) and 153 for 8 dec (Lawrence 53, Abbott 4-63) by three wickets

Dawson, whose dismissal for 57 at Trent Bridge on Saturday had been the turning point of that tense contest, once again fell short of sealing the deal when, with 20 runs still needed from 23 balls, he crashed Matt Critchley into Nick Browne's midriff at short cover, to offer Essex the most slender of late lifelines.

The tale of the tape was thus: Essex had begun the penultimate round with a deficit of 18 points, and with scant hope of closing the gap given that Surrey were at home to the relegation-bound Northants. And yet, after a clatter of morning wickets at the Kia Oval had condemned Surrey to the follow-on, Essex seemed dead-certs to capitalise on the champions' missed moment with their seventh win on the bounce, and slash that deficit to a meagre four points.

If the Vince reprieve, at 52 for 4, helped to snap Hampshire's game-brains back into place, then Dawson's let-off, 97 runs later, was the moment that Essex's belief visibly ebbed from their performance. Blow by blow, they were beaten back by two World Cup winners - men who were present in the dressing-room through England's 2019 triumph, and who know full well, by osmosis as much as through their own clear abilities, how to pace a chase that never threatened to tick over a run a ball. "It's just a different colour ball," as Paul Collingwood, England's assistant Test coach, put it recently when describing the ever-converging methods of the red- and white-ball games.

With his century in sight, Vince hoisted Cook handsomely over long-on for his second six, only to come unstuck in Critchley's subsequent over, hacking a skewed drive to Dan Lawrence in the covers. But even that seemed too little too late for Essex, especially when Umesh Yadav's brilliant sprawling effort at backward square off Dawson, on 97 at the time, was deemed to have been a bump-ball. Two balls later, Dawson crunched Critchley down the ground for his 14th four, and celebrated with a raise of the arms to put the seal on a truly mighty all-round season.

In the final analysis, Essex will know, however, that they blew a golden opportunity to take the title to a straight shoot-out. They claimed nine Hampshire wickets in the course of the day's play, after all, two of which had come in a perfunctory round-up of their first innings, seven hours and several lifetimes earlier in the day.

At that early stage of proceedings, with Chelmsford's replay screen gleefully showing footage of Surrey's slide towards their follow-on, Essex could smell the unease emanating from south London. Even as he was flicking off Tom Prest's bails to end an excellent knock on 108 and give Harmer his sixth wicket of the innings, Adam Rossington began sprinting for the pavilion to pad up, in a clear sign of how Essex intended their second innings to pan out.

Sure enough, Rossington re-emerged ten minutes later in a gambit for quick runs, but instead served up a tame three-ball duck that rather set the tone for a nondescript first ten overs of the declaration push, a passage that was coloured - perhaps inevitably - by the play within a play.

The notion of Cook's impending retirement had been shot down by Essex in a snotty statement on Thursday afternoon (the tone of which had perhaps been informed by their sudden realisation that the title was back up for grabs). However, that hardly discouraged a knot of photographers from congregating at the foot of the stairs to greet his (final?) emergence from the Chelmsford pavilion.

And for 38 deliveries spanning 45 minutes, Cook captured the attention - if not the zeitgeist - in a poignantly out-of-kilter display. Were this officially a valedictory innings, one might suggest it was an apt metaphor for Cook's raging-against-the-light career, as he fought valiantly against his natural inclinations, seeking to raise the tempo in the T20-prescribed fashion, only to lose his shape, and ultimately his wicket, in the process.

Cook thrashed and he yanked and, just once, he connected with a meaty lump through the line off Kyle Abbott as Essex finally reached the boundary from the first ball of the seventh over - a powerplay it had not been. But then, two balls after connecting on a cut that burst through Prest's hands at point, Cook wound into a cramped pull off Abbas, and under-edged through to the keeper.

His departure was another dead-pan vignette: an old cricketer leaving the crease, almost visibly resisting the urge to raise his bat as an uncertain tribute gathered momentum around the ground, before allowing himself just the hint of a grimace as he disappeared into the dressing-room. Whatever it is that remains of his storied career, he'd be giving nothing away just yet.

With the prologue done, then, the declaration push could begin in earnest, as a man rather better equipped for such a situation strode out for a Chelmsford farewell that had fewer caveats. Lawrence duly inside-edged his second ball through fine leg for four (it's how many, not how, as Cook would doubtless agree), but thereafter he batted like a man with a very personal reason to swipe some silverware from under the noses of his future employers.

Were it not for Essex's Championship ambitions, Lawrence might well be up at Trent Bridge right now, preparing for England's ODI against Ireland on Saturday. Instead he did his international prospects no harm at all in absentia, unfurling a range of preposterous cross-court forehands, including a full-blown helicopter whip for six off Abbott, to inject the impetus that Essex urgently needed. His 45-ball half-century drove the agenda in an 83-run stand in exactly 12 overs with Tom Westley, whose 45 from 49 ended when he launched Abbott to deep cover on the stroke of lunch.

The lead at that stage was a handy but still skinny 225, so more leverage was required. Enter Paul Walter at No. 4, who clouted Dawson over midwicket for six before being bowled next ball for 13, and Umesh Yadav, who bashed his first two balls over the Tom Pearce Stand for his fifth and sixth sixes of the match, then immediately holed out to long-on in search of a seventh. In between whiles, Critchley and Harmer misfired to deep cover to give Abbott a four-wicket haul, as the contest reset for round four.

Meanwhile, down at The Oval, Surrey by now were deep into their go-slow, with Rory Burns and Dom Sibley setting themselves to defend their title advantage at any cost, so Essex seized their chance to hurtle back into contention. Rossington set the standard with a wonderful grab down the leg-side, stretching with his left glove to prise out Tony Albert from Sam Cook's fourth ball, and then it was over to the inevitable Harmer.

The mere act of Harmer stepping up at the River End seemed to spook Fletcha Middleton, whose third-ball sweep was a harbinger of his imminent demise as it ballooned off a top-edge into space at square leg. Three overs later, he connected better - and worse - as Jamie Porter stooped at square leg to cling on, and Harmer made it two in the over when Nick Gubbins closed his face too early and chipped a leading edge to cover for 9.

Another harbinger followed, however, in Harmer's next over. Prest, yet to settle after his first-innings efforts, hacked impetuously down the ground but Walter at long-on couldn't cling on. This time, however, it didn't seem to matter; Harmer merely turned at the top of his mark and induced Prest into a flinch off the pads to short leg to leave Hampshire 32 for 4 and floundering.

And yet, Dawson's arrival to join Vince, allied to Essex's crucial lapses, would turn the afternoon's expectations upside-down.