Essex 295 (Browne 68, Walter 66, ten Doeschate 56, Stone 4-89, Hannon-Dalby 4-73) and 213 for 9 (Harmer 62*, Lawrence 55, Miles 4-62) lead Warwickshire
284 (Briggs 66, Harmer 4-89) by 224 runs
In normal circumstances - well, circumstances in which Simon Harmer is not involved - you would think that Warwickshire had a decent chance of victory going into the fourth day of this game.
Certainly, in adding 91 for their final two wickets and then reducing Essex to 36 for 5, they had clawed their way back into this match. Even a final-day target of 250 or so doesn't sound so intimidating for a side who chased down 333 against a Nottinghamshire side containing Stuart Broad only a week ago.
But such has been Harmer's dominance over the last few years that, in his period at the club, the highest fourth-innings score made to beat Essex is two. With 272 wickets coming at a cost of 19.62 since the start of the 2017 season - and remember, he only played six games in 2020 - he is a giant of the modern county game. If Warwickshire win this game, they will have achieved something no county side has in denying him in a first-class run-chase. You suspect Hanuma Vihari's encounter with Harmer may be crucial.
Harmer may already have produced the defining performance of this game. His unbeaten 62 has been the highest score in Essex's second innings and helped them rebuild from 93 for 6 when he came to the crease.
Warwickshire threw everything they had at him. And while Olly Stone inflicted a thumping blow to his helmet with a sharp bouncer, there was a determination about Harmer's batting - a sense that Warwickshire were going to have to chisel him out rather than wait for him to play a loose stroke - that has exemplified the uncompromising nature of an outstanding Championship match in which the initiative has changed almost every time you sensed that one side or the other had played the decisive hand.
Harmer's innings has been every bit as much about what he has not done as what he has. Noting that his colleagues perished by failing to play straight, pushing for the ball or hitting it in the air, he resolved to do none of those things. And while that reduced his scoring opportunities, he pulls and cuts well and is strong off his legs. There may have been moments when the bowlers thought they had the better of him but, with much of the pace having left this surface and the ball appearing to lose its menace after 25 overs or so, he was able to play the ball down so that even when his edge was found, he picked up runs down to third man. There's nothing pretty about Harmer's batting. But from an Essex perspective it really is quite beautiful.
It was Dan Lawrence who stopped the rot for Essex. Also adopting a largely risk-free approach, Lawrence demonstrated there was far more to his game that eye-catching strokes. Like Harmer's, it was a contribution notable for its denial as much as its timing or range. His half-century occupied 100 balls.
But, with much of the hard work done, Lawrence allowed Warwickshire back into the match when he embarked on an optimistic single only to be run out by Craig Miles' direct hit from mid-on. It left Essex only 148 runs ahead with seven wickets down. They were grateful to Harmer for boosting it significantly.
Warwickshire's attack looks infinitely more dangerous every time Stone has the ball. Even on this pretty sedate wicket, he has generated sharp pace and looked a class above anyone else on show. You can understand Will Rhodes, Warwickshire's captain, leaning heavily on him and perhaps these are exactly the sort of trials Stone must undergo to ascertain whether he really can withstand the rigours of Test cricket. But there were moments, when the spells became longer and the gaps between them shorter, when you did worry for him. Stone bowled 21 overs on the day including a final spell of seven. He has now bowled 83 overs in the last 10 days.
That Warwickshire cut the first-innings deficit to just 11 runs was largely due to Danny Briggs. He helped his new side add 91 for the final two wickets and eventually finished unbeaten on 66; the second-highest score of his first-class career and highest in the Championship. A period struggling to win selection in first-class cricket would appear to have led to him working hard in developing his batting and he has re-emerged as a valuable lower-order player. He is currently top of Warwickshire's batting averages in the competition.
He did not enjoy such joy with the ball. Unable to maintain the line and length that would have allowed his captain to set fielders around the bat, he delivered too many release balls to apply meaningful pressure. He gained little turn from an apparently dry surface, too. It will be intriguing to see what Harmer can get out of it on the final day but Briggs' relative lack of effectiveness combined with the impotence of Rhodes and Tim Bresnan increased the burden on the three main seamers.
By the time Ryan ten Doeschate was adjudged leg before to one from Stone that nipped back, it seemed Warwickshire had turned this game. At 36 for 5, Essex's lead was just 47 and the cream of their batting was gone. Alastair Cook and Tom Westley had both fallen to outstanding catches at point and mid-wicket respectively as they attempted to put away loose deliveries, before Nick Browne played slightly across one angled into him and Paul Walter edged a footless drive. Later Adam Wheater, having appeared to play himself in, let himself down a little by pulling directly to the man on the square-leg boundary.
But Harmer was in a less charitable mood. And maybe it is that stubborn nature as much as his talent which has proven such an asset to Essex over these last few years. The county game is played to a higher and more exacting standard for his presence. Warwickshire will have to pull off something special to deny him on the final day.

George Dobell is a senior correspondent at ESPNcricinfo