Durham 148 for 8 (Borthwick 100, Harmer 4-41) lead Essex 96 (Rushworth 3-13, Carse 3-37) by 52 runs
It's fair to assume that Durham were a little bit pumped for this one. Five long years ago, at the end of the 2016 season, these two clubs swapped places in the first and second divisions, and with it, their places in the national pecking order. Essex, promoted as champions, duly embarked on their run of three first-class titles out of four, while Durham's financially-imposed relegation brought a punitive end to their own indisputable golden age - between 2008 and 2013, they had racked up each of their three Championship titles, with three further one-day titles in the space of eight years.
And so, like a heavyweight title that had changed hands without any punches being thrown, there was something extra at stake at Chelmsford, in the two counties' first first-class meeting since September 2010 - a bygone era, when Durham themselves had been the two-times reigning champions, and when Essex's failure to force victory on the final day effectively opened the trapdoor to their own relegation.
By the close of a bruising opening day, the two combatants had punched each other senseless - 18 wickets falling all told, in a sea-change from the circumstances on this same ground last week, when 21 had been grudgingly handed over in the course of four full days. And though Essex were the side finishing with a surge in the semi-darkness, with four wickets falling for as many runs before the close, it was the performances of the two Durham survivors from that previous encounter 11 years ago who had hoisted their side into the ascendancy.
Scott Borthwick and Chris Rushworth have had contrasting experiences since that desperate relegation season. The former headed south to Surrey, in search of the new beginnings that might earn him a chance to add to that solitary Test cap, handed out in such invidious circumstances on England's whitewash Ashes tour in 2013-14. The latter held firm up north, keeping the home fires burning as he marched ever onwards in Durham's domestic annals - and with a superb analysis of 11-8-13-3 here, he moved along to 512 wickets, 15 shy of Graham Onions' all-time record.
But in a day dominated by the bowlers, nobody played a more glorious hand that the prodigal son Borthwick, who produced an urgent, emphatic innings of 100 from 129 balls, while his team-mates managed a grand total of 48 for 8 between them. Though he was crestfallen to be dismissed in the dying overs of the day, his efforts had driven Durham to a priceless lead of 52 by the close, and batting last against the chastened champions, they may yet need every run of that advantage.
Borthwick cracked 15 fours in his innings, as powerful on the sweep against the spinners - the ever-dangerous Simon Harmer in particular - as he was graceful on the drive, with his high-elbowed crunch through the covers off Ben Allison to move to 96 being the absolute pick of the crop. One ball later, he whipped a leg-stump delivery behind square, and ripped off his helmet with glee. After scores of 0 and 1 in an anticlimactic return against Nottinghamshire last week, this was the home-from-homecoming that he had dreamed of. Whether it will be a victorious one, however, remains to be seen.
Essex won the toss and chose to bat on the sort of morning that might have given them pause for thought against a bowling attack forged in the Arctic winds of Chester-le-Street. But then again, having endured the tedium of Worcestershire's only innings in last week's season opener, their bowlers had plenty reasons to pass the buck on that score, especially given the lack of complication with which Tom Westley had racked up 213 on the first two days of that game.
It took Rushworth just three deliveries to suggest to Essex that life wasn't going to be quite that placid, as Nick Browne dangled his bat uncertainly outside off, and detonated his own leg stump with a fat inside-edge. Three overs later, he extended Alastair Cook's uneasy start to the season by thumping a well-planted knee-roll to send him on his way for 6.
At the other end, Matt Salisbury - revisiting his roots after coming through Essex's academy as a teenager - had already scalped Westley for 4, via a flat-footed drive that betrayed his team's mindset, or lack thereof. Essex had parked such shots in grinding along to 207 for 3 on the opening day of the season, but Westley wasn't interested in relaying his groundwork. He and his team seemed in a collective hurry to get a move on today.
That became a rather more literal experience when Brydon Carse entered the fray in the 14th over. Generating sharp pace from the outset, his first-ball loosener had more heat that Paul Walter was anticipating, as he wafted an under-edged cut onto his stumps for 7. And before the over was out, Essex were 36 for 5 and facing humiliation. Carse's well-directed short ball thumped into an upraised bat as Ryan ten Doeschate ducked for cover, and a fast flat deflection fizzed to Ned Eckersley at third slip.
Throughout all of this, Dan Lawrence cut a phlegmatic figure at the non-striker's end - he'd seen it all before, in rather different surroundings, throughout England's winter exertions in Sri Lanka and India. By the time a rain flurry brought about an early lunch, Lawrence was batting like a man with a different agenda - he'd already cracked his first ball, from Rushworth, through wide long-on, and had added four more cleanly struck fours to stride along to 32 not out, with Adam Wheater solid alongside him in a sixth-wicket rescue-stand of 38.
Straight after the break, however, Essex were right back in the soup. Ben Raine's first delivery of the session was dangled outside off, for Wheater to nibble fatally to second slip for 18. But it was Salisbury's intercession, 11 balls later, that scuttled any hopes of a fighting total - a superb delivery that bit the seam on a full and tight length, lifting past the edge of a resolute block to trim Lawrence's bails and send him on his way without addition. At 74 for 7, there were only scraps left for Essex to fight for.
Harmer couldn't delay Durham's march, as he prodded limply to slip for a duck, and Ben Allison fared little better, as Rushworth found his edge too to finish with the outstanding figures of 3 for 13 in 11 overs. Only Sam Cook found any meaningful resistance with a free-spirited innings of 15 from No.10, but the end to his stay was savage, as Carse bend his back once more, and David Bedingham swallowed a flap off the eyebrows to slip.
Essex's total of 96 was their lowest at Chelmsford since 2014, and after Worcestershire had ended their 11-match home winning streak last week, a far greater ignominy awaited.
Durham's response faltered early, as Alex Lees fell early to Sam Cook, who found some sharp lift on the angle across the left-hander to prise him out for 5. But Borthwick joined Will Young in what appeared to be a game-seizing stand of 87. Between them, they surged past Essex's total with a riotous acceleration from the end of the 20th over, all but doubling the score from 46 for 1 to 98 in the space of six overs as Porter and Harmer were battered for nine fours between them.
But then, on 24, Young got too frisky against a sharp offbreak from Harmer, and flicked a leg-glance straight into Lawrence's lap at leg slip to break both the stand, and Durham's hot streak. One over later, Bedingham skipped down the pitch to Harmer, seeking to keep up the tempo, and holed out to Westley at long-on for a duck. And when Jack Burnham was skittled by a beauty from Cook, angling in and bursting round the edge of a full-faced block, Durhan were 114 for 4 and wobbling.
Borthwick, however, was having none of it. Two more crunching sweeps kept up the pressure on Harmer as he marched into the 90s, and a few overs later he had his moment of catharsis off Allison. His team-mates, however, could match neither his tempo or his endurance, as Eckersley joined the procession with a deflected lob to slip off Harmer. And with the light closing in, Borthwick's own resistance was finally broken. Lawrence, into the attack for a twin-spin assault, fizzed through his defences before cleaning up Carse one ball later with a ripping offbreak that sent a clear message about how this contest may yet play out in the second innings.
At 144 for 7, it seemed we were done for the day … but not so. With Prince Philip's impending funeral causing the first two days of this game to be extended, the players trooped back out at 7pm to finish off their allocation, and Durham's innings was all but finished off full-stop, as Ben Raine became Harmer's fourth victim of a quietly predatory display. If this is what we've been missing out on in the past 11 years of non-combatance, then Essex and Durham have gone a long way towards making up for lost time.
Andrew Miller is UK editor of ESPNcricinfo. @miller_cricket