An absorbing day’s championship cricket was dominated by two players as Leicestershire batsman Mark Cosgrove and Sussex fast bowler Jofra Archer conducted what felt at times to be a personal battle to put their side into the ascendancy.
The experienced Cosgrove, who before play started confirmed he had signed a one year contract extension with the Foxes until the end of 2019, closed on 122 not out, his second century in as many matches.
Archer, playing only his 12th first-class match, bowled with intelligent accuracy as well as hostility on an essentially good pitch to finish with 5-61 from 25 overs of unremitting effort.
Without his contribution, Sussex acting captain Chris Nash’s decision to exercise the away team’s right to bowl first would have been made to look thoroughly misjudged.
Sussex bowling coach Jon Lewis said: “I think we’ve had a good day on a pretty good pitch.
“We bowled nicely as a group, but David Wiese has pulled up a little bit sore, which is unfortunate, because he’s been bowling well recently and I think we could have bowled them out for 300.
“David has a little stomach muscle strain, which hopefully isn’t too serious. We’ll obviously have to bat well once we’ve bowled them out tomorrow.
“Jofra [Archer] is a fantastic talent, he bowls fast with bounce and movement. Everything about his action is very simple.
“He wants to play international cricket, he’s been very vocal about that, and the way he bowled today you can see why.
“He’s the best at his age  in the country. I imagine he’s on the West Indies radar and England’s radar, it’ll be his decision.”
The morning had seen Leicestershire openers Paul Horton and Harry Dearden bat through a rain-interrupted session during which only 17 overs were possible without being parted.
Once the shower clouds had cleared, however, Archer struck twice in the course of delivering eight consecutive overs from the Bennett End, during which he conceded only 11 runs.
He dismissed Dearden with a quick, rising delivery which seamed away from the left-hander, Chris Jordan holding a smart catch to his left at first slip, and produced a similar delivery which took the shoulder of Colin Ackermann’s bat to give Stiaan van Zyl a simple catch at third slip.
Cosgrove then had to fight hard to preserve his wicket, and was fortunate to survive after being squared up on a number of occasions, but once Archer came out of the attack, the Australian played with fluency and freedom, hitting eight boundaries in reaching his 50 off just 70 balls.
At the other end, the experienced Horton dug in, taking 126 balls to reach his own half-century, but was bowled driving loosely at an Archer delivery that seamed back to hit the top of off-stump.
Ned Eckersley was caught at mid-on trying to hit spinner Danny Briggs out of the attack, and both Mark Pettini and Tom Wells looked to be beaten by pace.
Cosgrove stood firm, however, reaching his century off 144 balls, and with Archer finally tiring, Zak Chappell’s late contribution saw the Foxes through to a third batting bonus point.