Northamptonshire 91 for 4 trail Sussex 175 (Carson 52, Sanderson 5-45) by 84 runs

The sight of fans at Hove for the first time in 20 months had done little to distract from a familiar story for Sussex when their top order succumbed to Ben Sanderson for the third time this month: they slid to 67 for 7 at lunch after opting to bat in the sunshine, and lost an eighth wicket two balls into the afternoon session. One returning punter put in his order at Greig's Café during the interval by asking for "a cup of tea, please - and do you know anyone who can bat?"

As luck would have it, the catering staff managed to pull some strings. Jack Carson and Henry Crocombe, Sussex's No. 9 and 10 with a combined age of 39, are part of the Covid generation whose first-class careers had been played entirely behind closed doors, with both making debuts in the Bob Willis Trophy last summer. Sussex's members had turned up just to make sure they existed in the third dimension, rather than being hermetically sealed in the club's online streaming service; a 99-run stand provided confirmation that they were indeed flesh and bones, and ensured a first-innings total that kept them in the game.

Crocombe, a tall right-arm seamer who removed Ben Curran with the new ball, played with a wristy flourish and was dropped twice as he chanced his arm, but it was Carson who looked like he had the potential to become a genuine allrounder. A 20-year-old offspinner from County Armagh, Carson first came to Sussex's attention eight years ago when Kyle McCallan, the former Ireland international, rang Ed Joyce to recommend a young batter at Waringstown CC in Belfast, whom he insisted was "pretty special".

"It's pretty hazy, but I think I said to the club that there was a young kid who wanted to have a look at playing for them, though spin was his secondary thing," Joyce, Sussex's captain at the time, recalls. "I didn't realise he was going to go over to England and go to school there but he's clearly done really well." Thanks to a sports scholarship at Hurstpierpoint College, Carson moved across the Irish Sea permanently for sixth form, and opportunities for the academy and the seconds were increasingly regular.

"We knew he could bowl a bit of offspin but he got his opportunity in the second team because he was scoring hundreds in the academy," James Kirtley, the club's T20 head coach and Ian Salisbury's assistant in other formats, explains. "And since then, Sals has worked his magic - and Sals really is a wizard. It's a wonderful partnership and double-act."

While his classical action and hard-spun offbreaks have caught the eye since last summer - in Rory Burns, Zak Crawley and Joe Root, he has dismissed three of England's top four - Carson's returns with the bat had been a disappointment, with a top score of 21 in his first 17 innings. Here, he was dropped early on, but an organised half-century which featured several compact back-foot punches through point for four dragged Sussex towards respectability and hinted at his potential to balance the side at No. 7 in years to come.

A first ovation from his home crowd - which included a recuperating Jofra Archer - made things even sweeter. "I've definitely been frustrated with how I've batted before today," he admitted. "Fans have just seen scorecards or live streams so having a crowd in was a great chance to show people in the flesh that I'm here to hang around with the bat." Unsurprisingly, it didn't take his team-mates long to suggest he only turns up when fans are in. "That line was pretty swift when I came off - if that's my lucky charm, so be it."

Carson has made clear that his ultimate ambition is to play Test cricket for England, even if Joyce holds out some hope that he may one day be an Ireland player. Kirtley suggests that a Lions call-up might not be too far away: "His skills are very good for a 20-year-old and I'm sure he will be recognised at an international level shortly, and rightfully. He's a very fine young prospect."

But his innings meant that the real star of the day had slipped - perhaps characteristically - under the radar. When Carson steered to third slip shortly before tea, it meant Sanderson had completed his third five-for in as many innings against Sussex, following his 10-wicket haul in the demolition job at Wantage Road. A late developer who had taken a solitary Championship wicket when Northants offered him a trial aged 26, Sanderson has been the image of consistency over the last five seasons and a first-class average of 20.47 demonstrates his skill with the new ball in particular.

"They'd rather go to Lord's than watch Northants for four days," Sanderson grumbled to The Cricketer last year when asked why he thought England's selectors had never been in touch despite his record, and while his age (32) and lack of pace mean international honours are unlikely to arrive, there are no county batters who relish the prospect of facing him early on.

Defying clear blue skies, Sanderson was devastating against Sussex's string of left-handers, coming round the wicket from the Cromwell Road End to angle the ball into the bat and then nip it away off the seam. Stiaan van Zyl and Travis Head, the two overseas players, both edged into the cordon, while Aaron Thomason was trapped lbw offering no shot and George Garton was smashed on the knee roll. Gareth Berg, Wayne Parnell and Tom Taylor shared the other five between them, benefitting from both the variable bounce on offer and some injudicious shot selection.

A wicket apiece for Sussex's young seamers and one late in the day for Carson - Rob Keogh, clipping a low catch to short midwicket - pegged Northants back, but they have an opportunity to secure a significant first-innings lead in the morning. Victory this week may be enough to nudge them ahead of Yorkshire and into second place in Group Three; after their promotion-that-wasn't in 2019, qualification for Division One would be another impressive feat.

Matt Roller is an assistant editor at ESPNcricinfo. @mroller98