Napier and Porter's hard yards revive Essex
Sussex 360 and 282 for 9 (Nash 92, Napier 5-86, Porter 4-82) lead Essex 320 (Westley 86, ten Doeschate 51, Ryder 51) by 322 runs
At one stage in this match, it looked as if Sussex were disappearing off into the distance over the South Downs. Building on a second significant score from opener Chris Nash, the lead at tea was 210 with seven wickets standing. That they were left relying on the last-wicket pair of Ajmal Shahzad and Steve Magoffin to chivvy and poke their way to the close, during an unbroken stand worth 40, tells you much about how competitive this game has been.
Essex will still have to chase more than the 320 they made in their first innings but they would have been left huffing and puffing in the face of a much steeper incline were it not for their two new-ball bowlers, Jamie Porter and Graham Napier, who claimed nine wickets between them while delivering more than two-thirds of the 68 overs that Sussex's second innings has so far lasted.
Porter and Napier are at opposite ends of their careers but, with Matt Dixon struggling to adjust to the slope and Essex's plethora of medium-pacers offering up a glut of bad balls, they shouldered the burden uncomplainingly.
Porter, in particular, looks a slip of a fast bowler but he showed a work ethic that would have made Alexey Stakhanov beam with pride, sending down an 18-over spell either side of tea. Napier, 36 and in his final season before retirement, managed 13 in a row and it looked as if Essex's pair of dray horses might be yoked together for the entire session until the niggling resistance put on by Shahzad and Magoffin forced Ryan ten Doeschate to give them a rest.
Sussex had been 165 for 2 and scoring at more than five runs an over before Ross Taylor became Porter's first victim, steering to second slip. On a pitch that still looked good for batting, Sussex then slipped to 242 for 9, the next six dismissals all bowled or lbw as Porter and Napier utilised a hint of reverse swing and targeted the stumps.
Porter, who once bowled a 22-over spell in club cricket for Fives & Heronians, kept charging in up the hill from the Sea End, still searching for a maiden five-wicket haul despite having taken 79 first-class wickets since making his Essex debut at the end of 2014. Ten Doeschate did not have to do much persuading. "It was me saying to him, 'I dare you to try and get the ball out of my hand'," Porter said, blinking slightly deliriously afterwards.
The final day is neatly poised but if Sussex are able to secure a first win of the season, then some credit will have to go to the south-coast sunshine. Not the south coast of England - although Hove has basked under clear skies for most of this match - but rather the southern cape of Africa, where Nash spent five weeks earlier this year soaking up the rays, along with a few batting tips from former South Africa opener Gary Kirsten.
Nash, still wearing Matthew Hobden's No. 19 short, fell eight runs short of matching his efforts on day one but he kept his side in what has been a fiercely contested match. It was another chanceless innings, a bang on the head from a Porter bouncer the closest Essex came to upsetting him until Napier pinned him in front after nearly four hours at the crease.
Nash's entry in The Cricketers' Who's Who says that if he wasn't playing cricket he would be sunbathing and he surely had the opportunity to work on his tan as well as his game while at Kirsten's academy in Cape Town. Having tallied 211 runs in his first appearance of the season, he already has a pretty decent excuse to return there next winter.
Talk about helmets and player protection has swirled in recent days but there was a reminder of the important job they do when Nash was felled by Porter. Nash was hit on the peak of a new-style helmet but was able to continue after some treatment and he credited the fixed grille for saving him from greater injury.
Essex had resumed in the morning still trailing by more than 100 runs and only a gritty stand of 89 between ten Doeschate and Napier for the eighth wicket prevented Sussex from taking a much stronger grip on proceedings. It took a brilliant catch from Danny Briggs at first slip - a new addition to the cordon - to remove ten Doeschate but the captain's half-century helped Essex to recover from 219 for 7 on the second evening and get to within 40 runs of Sussex's first-innings 360.
Napier may be a little more crinkly around the eyes and a little more stocky in stature but he still ably fills the "local legend" brief in county cricket. His batting was more watchful foil than wrecking ball - though a top-edged hook at Magoffin did sail for six - as he hung around for an hour and 40 minutes before becoming Essex's ninth man out. But his work for the day was far from over.
Alan Gardner is an assistant editor at ESPNcricinfo. @alanroderick